ten/tain/tin

hold, keep

Spelled ten, tain, tin · tenere 'hold, keep'

Latin tenere means hold: contain holds things together, retain holds them back, and tenacious describes someone who keeps holding on.

Words built from it

tenacious — holding firmly to something; unwilling to give up
Latin tenere 'hold' → tenax 'holding fast' → tenacious
tenable — able to be defended with good reasons
Latin tenere 'hold' → French tenir 'hold' + -able 'capable of'
contain — to hold or have something inside
Latin continere: con- 'together' + tenere 'hold' → French contenir → contain
retain — to keep possession of something
Latin retinere: re- 'back' + tenere 'hold' → French retenir → retain
detain — to hold someone back or keep someone in custody
Latin detinere: de- 'away, back' + tenere 'hold' → French detenir → detain
sustain — to support or keep something going
Latin sustinere: sub- 'from below' + tenere 'hold' → French sustenir → sustain
abstain — to choose not to do or take something
Latin abstinere: abs- 'away' + tenere 'hold' → French abstenir → abstain

tenuous — Comes from Latin tenuis (thin), not from tenere (hold), the root taught here.
tender — Contains ten, but comes from Latin tener (soft, delicate), not tenere (hold).