Meaning of BREAK-IN in English
[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. 2012