What's the plural form of compensatory lengthening? Here's the word you're looking for.
Answer
The noun compensatory lengthening can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be compensatory lengthening.
However, in more specific contexts, the plural form can also be compensatory lengthenings e.g. in reference to various types of compensatory lengthenings
or a collection of compensatory lengthenings.