The term 'ilare' is an Italian music term and it shows up in Beethoven's Sonata Nr. 16 in Simon and Schuster 1935 Arthur Schnabel, Editor Vol 1.
I can't find it in any dictionary....
Yes, Brian, sorry. I forgot to tell you that I checked the word and it wasn't there. But I thought you could find it useful for other related terms and to check allegro and allegretto