# Name for words without squared symbols

Is there a common name in combinatorics for words that do not have square of size 1 ? That is words such that no symbols appears twice in a row or, more formally, words not in $$\bigcup_{s\in\Sigma} \Sigma^* s s \Sigma^*$$ where $$\Sigma$$ is our alphabet.

• I propose calling the occurrence of a repeated letter a “hiccup” and correspondingly calling your language hiccup-free. Jan 31 at 17:38