(Internet, Wiktionary and WMF jargon) citation needed

reliance, trust, confidence

to trust

to doubt / to have doubts / to be doubtful / to distrust, to mistrust / to call (a matter) into question

authority, source (of a quotation etc.)

sex, gender / (grammar) gender

information / news / gossip

need, necessity / essential

key, important point / essential piece of something, requirement

the pin or rivet holding the spines of a folding fan together / (by extension) a pivot, cornerstone, keystone / a pin, often decorated, holding the handle to the tang of a katana