ascendo

Ascendo, ascendere, ascendi, ascensum is third conjugation: ad plus scando, "climb". The compound weakens the a of the stem to e, which is why the perfect is ascendi rather than anything with an a in it, and why descendo and conscendo look the way they do.

Construction: normally in with the accusative for the thing climbed - in montem ascendere, in navem ascendere, in equum ascendere - though verse will use a bare accusative or a dative. Its exact opposite is descendo, and the pair get used together constantly for hills, ships and social standing. The corpus is largely ecclesiastical, so watch for ascensio, the Ascension, and for ascendere as a plain "go up to Jerusalem". English took ascend, ascent, ascendant and, from the same root, scan and scale.