Etymology First attested in 1645; adapted from either French mariner or the earlier attested Italian marinare (“to pickle, marinate”) (see -ate (verb-forming suffix) and -ate (adjective-forming suffix)), from Late Latin marina (“brine, salt water”), short for aqua marina (“sea water”), from Latin marinus (“marine, of the sea”), from Latin mare (“the sea”) from Proto-Indo-European *móri (“the sea”).
1
Ergative To allow a sauce or flavoring mixture to absorb into something; to steep or soak something in a marinade to flavor or prepare it for cooking.
You'll get a better flavour from the chicken if you marinate it first.
After the chicken has marinated for two hours, discard the remaining marinade.
2
Ambitransitive To allow a substance to be absobed into the hair or scalp.
oblucy: "vinegar... to marinate the scalp... oil... to lubricate the scalp..."1992 September 3, Laura Potler (GSFC), “own private idaho”, in alt.peeves (Usenet):
Let your scalp marinate while you shave.2000, The Doctors Book of Home Remedies for Men: From Heart Disease and Headaches to Flabby Abs and Fatigue, Random House Publishing Group, page 243:
1 more example
Wrap a dry towel around the wet towel, and let your child's hair marinate for an hour.2014 [2006], Ellen Sandbeck, Organic Housekeeping: In Which the Non-Toxic Avenger Shows You How to Improve Your Health and That of Your Family, While You Save Time, Money, and, Perhaps, Your Sanity (ebook), Scribner, page 400:
3
Ambitransitive Of a substance, to absorb into the hair or scalp.
a rejuvenating oil you use to saturate your hair and let it marinate from 15 minutes to 2 hours2003 November 22, fig, “I met THE Philip B. today!”, in alt.fashion (Usenet):
[...] hair rather than the scalp, but as always, experiment. You can also play around with how long you leave the mixture on your head — some people have better results after letting the ACV marinate for a few minutes.2015, Savannah Born, Shampoo-Free: A DIY Guide to Putting Down the Bottle and Embracing Healthier, Happier Hair (ebook), Skyhorse Publishing, unnumbered page:
4
Of ideas or feelings, to mentally develop over time.
5
Figuratively, Informal Especially of a haircut, to settle in and for one to get used to it.
It's not a bad haircut! You just got to let it marinate!
Etymology First attested in 1645; adapted from either French mariner or the earlier attested Italian marinare (“to pickle, marinate”) (see -ate (verb-forming suffix) and -ate (adjective-forming suffix)), from Late Latin marina (“brine, salt water”), short for aqua marina (“sea water”), from Latin marinus (“marine, of the sea”), from Latin mare (“the sea”) from Proto-Indo-European *móri (“the sea”).