Synonym for ascertain is "prove"

define [verb]

means "activity"
render precisely, determine, characterise, characterize, ascertain, elucidate

- conjugate verb define

divine [verb]

means "find out"
discover, determine, ascertain

- conjugate verb divine

establish [verb]

means "verify"
prove, ascertain, demonstrate, substantiate, learn, determine

- conjugate verb establish

inspect [verb]

means "examine"
ascertain, determine, fathom, sound, investigate, probe

- conjugate verb inspect

learn [verb]

means "perception"
master, acquire, ascertain, pick up, get, detect

- conjugate verb learn
- translate learn

prove [verb]

means "activity"
verify, ascertain, corroborate, confirm, certify, demonstrate

- conjugate verb prove

see [verb]

means "perception"
recognize, determine, ascertain

- conjugate verb see
- translate see

sound [verb]

means "activity"
examine, ascertain, determine, fathom, inspect, investigate

- conjugate verb sound

take [verb]

means "activity"
determine, ascertain, fix

- conjugate verb take
- translate take

tell [verb]

means "activity"
deduce, ascertain, discern, distinguish, differentiate, compute

- conjugate verb tell

trace [verb]

means "investigate"
discover, determine, ascertain, find out

- conjugate verb trace

ascertainable [adjective]

means "discernible"
distinguishable, perceptible, visible, appreciable, apparent, recognisable, recognizable, tangible

appreciable [adjective]

means "discernible"
distinguishable, perceptible, visible, ascertainable, apparent, recognisable

calculable [adjective]

means "measurable"
ascertainable, estimable, predictable, accountable, computable

established [adjective]

means "proved"
ascertained, approved, authenticated, confirmed, determined, verified

knowable [adjective]

means "comprehensible"
discernible, apparent, conceivable, fathomable, ascertainable, recognisable

measured [adjective]

means "rhythmical"
uniform, slow, stately, deliberate, ascertained, guarded

recognisable [adjective]

means "discernible"
distinguishable, perceptible, visible, ascertainable, apparent, appreciable

recognizable [adjective]