What is a trailer seals?

Whenever we encounter a new word it is ok to create a reaction of curiosity expressed in the face. I admit that my vocabulary isn’t that wide so whenever I encounter words I’ve never used before I want to slap the face of the person I’m talking to. I want to ask from what planet did she or he heard that word, and what the hell does it mean? But I always end up being ashamed of myself, because that word was only usual and typical, it was my bad. Lately I have encountered the word trailer seals. They are two words that if defined word by word can be easily understand by my brain. But if you combined it a new word is formed. But either way around I somewhat know what it mean. It is a seal of a trailer to protect the contents of the trailer. It is somewhat a lock to prevent people from entering or filtering the trailer. How about you, what is your own version when it comes to defining the word trailer seals?