Adverb

(-)

Mainly or chiefly; for the most part; usually, generally, on the whole.

*{{quote-magazine, date=2013-06-29, volume=407, issue=8842, page=72-3, magazine=(The Economist)

, title= A punch in the gut , passage=Mostly , the microbiome is beneficial. It helps with digestion and enables people to extract a lot more calories from their food than would otherwise be possible. Research over the past few years, however, has implicated it in diseases from atherosclerosis to asthma to autism.}}

(obsolete) To the greatest extent; most.

* 1817 , , Northanger Abbey , [http://books.google.co.uk/books?id=mDUbXHRIbRIC&dq=northanger+abbey+search+austen&pg=PP1&ots=EDH1Xu36el&sig=J7fVUwXmydAD36S8oLTWv2-ICNk&hl=en&sa=X&oi=book_result&resnum=1&ct=result#PPA163,M1]:

She was to be their chosen visitor, she was to be for weeks under the same roof with the person whose society she mostly prized [...]!