| Definition -
A grammatical mood that is used to express a plea, insistence, imploring, a wish, desire, purpose, or intent.
1. It doesn't exist in English, but it is found in Hebrew. The mood is translated into English using phrases such as let us - e.g. Let's go into the cave.
Oxford English Dictionary - The term's first citation is from 1852:
"The characteristic of the Cohortative is a long a."
(Gesenius' Heb. Gram. (Eng. transl.) 81)