Commonly used in compound terms such as ブレストパッド (breast pad) or ブレストケア (breast care), rather than as a standalone body-part word in everyday conversation.
Breast pads are convenient to use while nursing.
Abbreviation of ブレストストローク (breaststroke). Used in swimming contexts.
See also: ブレストストローク
He won the gold medal in the 100-meter breaststroke.
She swam the breaststroke at the competition.