noun[usually in singular]
late 16th century: from ascend, on the pattern of the pair of descend, descent
Remember that ascent and the related words ascend and ascendant begin with asc-.
Do not confuse ascent with assent. Ascent means 'the action of rising or climbing up' (the ascent of Everest), whereas assent means 'approval' or 'agreement' (he nodded his assent).