'ament-shaped' is a compound formed from the noun 'ament' and the past-participle adjective 'shaped'. 'ament' originates from Latin, specifically the word 'amentum', where 'ament-' originally meant 'a thong, strap' (later used in botanical Latin for a catkin); 'shape' originates from Old English 'sceapian' (Proto-Germanic *skap-), where the root meant 'to form, create'.

'ament' passed into English via Medieval/Modern botanical Latin from Latin 'amentum' and came to denote a 'catkin' (a slim, drooping flower cluster). 'shaped' developed from Old English 'sceapian' into the Modern English 'shape' and the past-participle form 'shaped'. The compound 'ament-shaped' therefore combines the inherited botanical noun with the modern participial adjective to mean 'having the shape of an ament'.

Initially, Latin 'amentum' referred to a 'thong' or 'strap'; in botanical usage it came to denote a strap- or droplet-like flower cluster (a catkin). Over time, combining it with 'shaped' produced the descriptive adjective 'ament-shaped', retaining the sense 'catkin-like' in modern botanical English.