From http://www.thefreedictionary.com :
tenet [ˈtɛnɪt ˈtiːnɪt]
a belief, opinion, or dogma
[from Latin, literally: he (it) holds, from tenēre to hold]
1. One that pays rent to use or occupy land, a building, or other property owned by another.
2. A dweller in a place; an occupant.
3. Law One who holds or possesses lands, tenements, or sometimes personal property by any kind of title.
tr. & intr.v. ten·ant·ed, ten·ant·ing, ten·ants
To hold as a tenant or be a tenant.
I hate to be that guy, but the founder of AshleyMadison.com was on the Q on CBC radio this morning, and quite eloquently defended the service his company provides to the public. Unfortunately, he on a couple of occasions spoke about how monogamy is a great "tenant" of Western thought as pertains to romantic love and marriage.
Uh, dude, monogamy is not a tenant of anything. You mean to say it's a tenet of Western thought.