Glossary
No jargon, no assumed knowledge. Every term you'll encounter in a product spec or review, explained in plain language.
33
terms defined
YKK's water-resistant zipper line, where the zipper teeth themselves are coated with a polyurethane laminate to slow water ingress.
In practice: Resists splashing and light rain but allows water through under sustained pressure or if the zipper faces upward in a downpour. Fully waterproof seals require a different zipper class entirely.
YKK's waterproof zipper line, with large molded teeth that compress into an airtight seal when the zipper is closed.
In practice: Used in submersible dry bags and fully waterproof packs. Stiffer to pull than a standard or AquaGuard zipper, and it benefits from occasional lubrication.
A dense cluster of stitches applied at high-stress points — strap attachments, grab handles, zipper ends — to prevent tearing under load.
In practice: Among the cheapest quality signals to verify. Run a finger over every strap attachment and grab handle; their absence is a manufacturing tell.
A bag opening style where the main compartment unzips along three sides, letting it open flat like a suitcase.
In practice: Makes packing and finding items easier — you can see everything at once without digging.
A zipper made from continuous nylon or polyester coil rather than individual molded teeth — flexible, light, and the most common bag zipper. Reverse coil flips the coil so the teeth face inward, producing a cleaner exterior look and better resistance to water and debris.
In practice: Reverse coil is what most premium bags use; standard coil is what most budget bags use. Both can be paired with AquaGuard coating for water resistance.
A strap that cinches a bag's contents inward, reducing volume and stabilizing the load.
In practice: Reduces sway, lowers carry profile for overhead bins, and makes a half-empty bag feel less heavy. Distinct from packing cubes, which compress contents inside the bag.
A family of durable nylon fabrics made by Invista. The denier number (e.g., 500D, 1000D) indicates yarn thickness.
In practice: Higher denier = heavier but more abrasion-resistant. 500D is a common balance point for everyday carry.
A row of looped webbing stitched to the exterior of a bag, creating multiple attachment points.
In practice: Useful for clipping gear, water bottles, or accessories externally with a carabiner.
A unit measuring the weight of a single thread of fabric per 9,000 meters. Higher denier means thicker, heavier thread.
In practice: A 200D bag is lighter and less abrasion-resistant than a 1000D bag. Neither is inherently better — it depends on your use.
A chemical finish applied to fabric that causes water to bead up and roll off the surface rather than soaking in.
In practice: Repels light rain but wears off with washing — and does not seal seams or zippers. Restored with cheap reproofing spray.
Dyneema Composite Fabric (DCF), formerly Cuben Fiber, is a laminate of Dyneema fibers between two polyester films — extraordinarily strong in tension and dramatically lighter than nylon at equivalent strength.
In practice: Resists tearing and water but abrades faster than woven fabrics like Cordura. Excellent for ultralight use, less suited to bags set down on rough surfaces daily.
A rigid or semi-rigid panel inside a backpack — typically foam, plastic, or aluminum — that gives it structure.
In practice: Helps the bag hold its shape when empty and transfers load from shoulder straps to your back more evenly.
The system of components — shoulder straps, back panel, hip belt, sternum strap, and load lifters — that transfers a bag's weight from the shoulders onto the body.
In practice: A well-engineered harness on a heavier bag carries a load more comfortably than a lightweight bag with a poor one. Empty weight matters less than how the harness moves the load.
A padded strap that wraps around the hips, designed to shift pack weight from the shoulders onto the stronger hip structure.
In practice: Only works effectively when the bag torso length matches yours — otherwise the belt sits above the hip crest and contributes little.
A flexible water reservoir, typically 1.5–3 liters, carried inside a bag with a drinking tube routed through a port to a shoulder strap.
In practice: Removes the friction of stopping to drink. Requires a compatible sleeve and port — a bottle pocket is not a substitute.
A water-resistance rating where the digit runs 1 to 8, and an X in place of the first number means dust resistance was not tested. IPX5 and IPX6 survive water jets; IPX7 and IPX8 survive submersion.
In practice: A bag marketed as waterproof with no published IP rating is usually only water-resistant. Ask for the number.
A small leather or rubber patch with two slits on the front of a bag, originally an attachment point for clipping on gear like a carabiner or light.
In practice: On many bags it is now decorative and holds nothing. Useful only if you actually clip something to it.
Short angled straps connecting the top of the shoulder harness to the top of the bag.
In practice: Pulling them tighter brings the bag closer to your center of gravity, reducing the forward pull on your shoulders.
Modular Lightweight Load-carrying Equipment. A grid of horizontal webbing loops on a bag's exterior, originally a military spec.
In practice: Lets you attach compatible pouches and accessories directly to the bag body. Adds external clutter and reads as tactical — useful for outdoor or specialist carry, often out of register for everyday or professional contexts.
A bag design where the main compartment is accessed via a U-shaped zipper on the front face of the bag.
In practice: Opens like a book, giving full access to contents without removing the bag.
A horizontal sleeve on the back of a bag that slides over the extended handle of rolling luggage, letting the roller carry both.
In practice: One of the most underrated travel features — eliminates the asymmetric load of a backpack carried while pulling a roller. Cheap versions are too narrow to fit standard trolley handles.
A weave pattern where reinforcing threads are interwoven at regular intervals into a finer fabric, producing a visible grid that stops a tear from propagating.
In practice: A common construction across nylons and polyesters at varying deniers. The grid is a structural feature, not a quality marker on its own — denier and coating still determine durability.
A high-tenacity nylon yarn produced by Hyosung, often used as a lighter, stronger alternative to standard Cordura at the same denier.
In practice: Comparable abrasion resistance to Cordura at noticeably lower weight, at slightly higher cost. Common in ultralight bags that want durability without going to a laminate.
A closure where the top of the bag folds down multiple times and fastens with a buckle, creating a water-resistant seal.
In practice: Volume-adjustable as contents change. Not fully waterproof at the fold — more water-resistant than sealed, less than submersible.
A horizontal strap connecting the two shoulder straps across the chest.
In practice: Stabilizes the bag and keeps shoulder straps from slipping outward, especially useful when moving quickly.
A bag design where items are loaded through an opening at the top, often covered by a lid or drawstring.
In practice: Common in hiking packs. High capacity and weather-resistant, but requires unpacking to reach items at the bottom.
The distance from the C7 vertebra (base of neck) to the iliac crest (top of hip bones).
In practice: The key measurement for fitting a backpack. A bag sized for your torso length positions the hip belt correctly and distributes weight efficiently.
The total internal capacity of a bag, measured in liters, calculated by filling the bag with sand or similar material.
In practice: Includes all pockets and compartments. The rated volume and the usable space for your actual contents will differ.
Cotton canvas saturated or coated with a wax compound that fills the spaces between fibers, producing a water-resistant surface that develops a distinctive patina with use.
In practice: Water-resistant, not waterproof. Traditional and dry finishes patina dramatically and need periodic reproofing; emulsified finishes need less maintenance but age more subtly.
Flat woven nylon or polyester strap material, used for attachment points, adjustable straps, and load-bearing structures across the bag.
In practice: Wider webbing distributes load better. Hip belts and shoulder straps use heavier webbing; daisy chains and strap keepers use lighter.
A join that fuses two fabric panels with heat instead of stitching through them, leaving no needle holes.
In practice: The seam itself is waterproof, where a sewn seam needs tape over the stitch line. RF welded, high-frequency welded, and ultrasonic welded name the heat method, not different constructions.
A laminated composite fabric made by Dimension-Polyant, combining a face fabric, a polyester film layer, and a backing.
In practice: Lighter than equivalent Cordura, inherently water-resistant rather than just coated, and noticeably stiffer. Has a distinctive sail-cloth look.
The world's largest zipper manufacturer, producing an estimated 50% of all zippers globally.
In practice: YKK zippers are more consistent and durable than generic alternatives. YKK Aquaguard means the zipper element itself is water-resistant.