This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
蹍 combines 足 (foot) with 展, which likely contributes the sound. The exact historical development is uncertain.
With 足 (foot) on the left and 展 (spread, expand) on the right, picture a foot stepping and spreading its weight as it treads.
For テン, imagine a foot stepping on ten tiny pebbles: ten -> テン, and each step spreads the foot's weight.