cotter pin retaining pin

gudgeon pin [= crosshead pin]

pin-for-pin

pin-to-pin leakage

pin-to-pin reducer

accidental transmission engagement

air-to-ground engagement

angle of engagement

anti shore engagement

appraisal and engagement system

area of engagement

assurance engagement

attempted engagement

audit engagement

axis of engagement

back engagement

beyond visual range group engagement

boundary of engagement

brake engagement

break of an engagement