summit
巓 centers on the highest point of a mountain: the summit or peak.
巓 combines 山 (mountain) with 顚, which likely contributes the sound and may relate to the top or crown of the head, reinforcing the idea of a mountain summit.
The top is 山 (mountain), and the bottom 顚 looks like a head with a crown. Picture the crown of a mountain: its summit.
For テン, imagine ten mountain peaks lined up, and the highest one is the summit: ten -> テン.
summit (of a mountain)