When there should be a word for something, but there isn’t, it is called a lexical gap! A lexical gap is also called a lacuna and is an absence of a word in a particular language. Lexical gaps include untranslatable words and accidental gaps.
Every language has words or terms that don’t hold the same significance or meaning when translated and some words don’t translate at all. An accidental gap is a word or other form that doesn’t exist in a language that is expected to exist given the grammatical rules of the language.
An example of an accidental gap is that the suffix “al” can be added to a verb to make it a noun; as in arrive to arrival or recite to recital. However, describe cannot be changed to describal. This is an accidental gap in the grammatical rule.
There are many forms of accidental gaps that exist. Phonological gaps exist and are categorized under accidental gaps. Languages and grammatical rules can be really tricky. Next time you can’t think of a word you can blame it on the lexical gap. You’ll sound impressively smart.