Cargo Securement Glossary

About this glossary

The terms here come from federal cargo securement regulations, freight industry practice, and the topics covered on this site. Each entry includes a plain-English definition and, where the term has a specific federal meaning, a note on the regulatory source.

A word of caution: many cargo securement terms are used loosely in the field. "WLL" sometimes gets conflated with break strength. "Blocking" and "bracing" are often used interchangeably when they describe different functions. "Tiedown" covers both the device and the act of securing. Where the federal rule uses a term with a specific meaning, this glossary tries to stay close to that definition rather than the casual shorthand.

Terms from the federal regulation

49 CFR Part 393 Subpart I defines several terms specifically for cargo securement. Working load limit, aggregate working load limit, direct tiedown, indirect tiedown, blocking, bracing, and dunnage all have regulatory context that matters when you're reading the rule or interpreting a compliance question.

When this glossary uses those terms, it's referencing the regulatory meaning. For any term that has compliance implications — WLL, tiedown classification, blocking requirements — verify the current definition against the eCFR text rather than relying on the glossary summary alone. The linked source notes in each entry point to the relevant section.

Operational terms from freight practice

Some terms here are operational rather than regulatory: shipper load and count, seal number, delivery exception, load shift, cargo claim, Bill of Lading. These don't have a specific federal definition the same way working load limit does, but they come up frequently in the context of cargo securement and freight documentation, so they belong in the same reference.

The definitions for operational terms reflect common freight industry usage, which can vary by carrier, shipper, and region. Where a term has multiple possible interpretations, the entry tries to note the context that applies on this site.

Terms that are often confused

A few definitions worth flagging because they're frequently mixed up:

Working load limit vs. break strength: WLL is the rated safe working capacity — typically a fraction of the break strength. Never use break strength as your planning figure. The WLL is what counts for aggregate WLL calculations.

Direct vs. indirect tiedowns: A direct tiedown connects to the cargo at both ends. An indirect tiedown (over-center tie) passes over the cargo and anchors on both sides of the deck. The distinction affects how capacity is credited under the federal rule.

Blocking vs. bracing: Blocking uses a structure against the cargo to prevent forward, rearward, or lateral movement. Bracing uses a compression member between the cargo and a structural part of the vehicle. Both are load-control methods that can supplement or partially substitute for tiedowns in some situations.

How to use this glossary

If you're looking up a term for a compliance question, use the source links in each entry to verify the current federal definition at ecfr.gov. Glossary definitions summarize the source — the source is what matters in an enforcement or claim context.

For broader coverage of the topics these terms come from, see Cargo Securement Rules, Working Load Limit, Tie-Down Requirements, and Cargo Claims.