Meaning of the word "base form" in English

What does "base form" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

base form

US /beɪs fɔrm/
UK /beɪs fɔːm/

Noun

the simplest form of a verb, without any endings or modifications, used as the infinitive or in certain tenses

Example:
The base form of 'running' is 'run'.
In the sentence 'They sing beautifully', 'sing' is the base form of the verb.