1/ ten means tightened/stretched/correctly tuned/holding on. tenor (strong voice), tenacity/tenure (holding on), tone/tune.
2/ ten ≈ tain (holding on): contain (→ content), obtain, abstain (abs = away, so “let go”), detain (de = down, so “keep from”, detention)
3/ (cont) pertain (per = thru, so “always held” → “belong”), entertain: keep the vibe among (enter) people, sustain (sus = from below).
4/ ten ≈ tin: continue. tend (stretched): tendency (pulled in one direction), tender (easy to cut, gentle/weak/kind, v: offer help).
5/ at (towards) +tend (offer) = attend/attention. pre (before) + tend (feel tension) = pretend. ex (to outside) + tend (stretch) = extend.
6/ in (mind) +tend (tighten) = intend (fix the mind to). in also means “stronger”: intense.
7/ con (with others) + tend (tension) = contend (debate, oppose). This is different from content (comes from contain)