מילים or מילות?
I have seen both, but been corrected from one to the other. Whats the deal?
Let's start by clarifying: מילה is feminine. The plural form of which is מילים.
If it is in a construct state (צורת סמיכות - Tzurat Smihut), it becomes מילת (Milat), or מילות (Milot) in plural.
For example - מילת קישור, which means Conjunction (in grammar). The construct state indicates the noun (מילת) belongs to the second word (קישור). A literal translation of מילת קישור could be "word of connection". The plural form would be מילות קישור (Milot Kishur - Conjunctions).
Another, less confusing example, can be עוגה (Uga - cake). On it's own it remains עוגה, but if you wanted to say cheese cake, it becomes עוגת גבינה - Ugat Gvina - cake of cheese. You can read more about the subject here: https://en.wikipedia.org/wiki/Construct_state
I hope this helps.