Second (such as 'you' ) and third (such as 'he/she') persons in singular of the indefinite preterite indicative mode for the verb amesetar . See verbs/amesetó .
It means that it no longer rises and maintains the same height or elevation. It is maintained at the same level or at the same height. That forms a plateau.
AMESET third singular person of the indefinite past of the verb AMESETAR, which does not grow, which stops growing