drum:  Belying the total lack of similarity between the instruments, drum, trumpet, and trombone seem to be closely related. Drum appears to be a shortening of a slightly earlier English word drumslade ‘drum, drummer’, which was borrowed from Low German trommelslag ‘drumbeat’. This was a compound noun formed from trommel ‘drum’ and slag ‘hit’ (related to English slay).
An alternative view is that English simply acquired the word from Middle Dutch tromme. Both these Germanic forms meant simply ‘drum’, but the picture becomes more complex with Middle High German tromme ‘drum’, for originally this had the sense ‘trumpet’, and what is more it had a variant form trumbe (its ancestor, Old High German trumpa, ultimate source of English trumpet and trombone, only meant ‘trumpet’).
So the picture that emerges is of a word that originally referred in a fairly undifferentiated way to any musical instrument that made a loud noise. => trombone, trumpet
1540s, probably from Middle Dutch tromme "drum," common Germanic (compare German Trommel, Danish tromme, Swedish trumma), probably of imitative origin. Not common before 1570s. Slightly older, and more common at first, was drumslade, apparently from Dutch or Low German trommelslag. Machinery sense attested from 1740, from similarity of shape.