The Collaborative International Dictionary of English v.0.48:
Ultima \Ul"ti*ma\ ([u^]l"i[i^]*m[.a]), a. [L., fem. of ultimus last.] Most remote; furthest; final; last. [1913 Webster] Ultima ratio [L.], the last reason or argument; the last resort. Ultima Thule. [L.] See Thule. [1913 Webster]