Synonyms: signally, notably; mainly. Especially,chiefly,particularly,principally refer to those cases that seem to be significant. Especially and particularly single out the most prominent case or example (often in order to particularize a general statement): Winter is especially severe on old people. Corn grows well in the Middle West, particularly in Iowa. Chiefly and principally imply that the general statement applies to a majority of the cases in question, and have a somewhat comparative force: Owls fly chiefly at night. Crime occurs principally in large cities.
c.1400, from O.Fr. especial "pre-eminent, important," from L. specialis "belonging to a particular kind or species," from species "kind." Latin words with initial sp-, st-, sc- usually acquired an e- when borrowed by O.Fr.
[i-spesh-uh-lee] 
ə