propionic acid
Concise Oxford English Dictionary © 2008 Oxford University Press:
propionic acid /ˌprəʊpɪˈɒnɪk/
▶noun Chemistry a pungent liquid organic acid produced in some forms of fermentation.
– origin C19: from Fr. propionique, from Gk pro ‘before’ + piōn ‘fat’, it being the first member of the fatty acid series to form fats.
'propionic acid' also found in these Oxford entries:

