Meaning of BREAK-IN in English

BREAK-IN

[break-in] n (1856) 1: the act or action of breaking in "a rash of ~s at the new apartment house"

2: a performance or a series of performances serving as a trial run

3: an initial period of operation during which working parts begin to function efficiently

Merriam-Webster English vocab.      Английский словарь Merriam Webster.