Rect and Recti.
60. What does Retro signify?
Backwards, as retrospect and retrograde.
61. What does Se signify?
By itself, as separate, seclude, etc.
62. What prefixes signify Half?
Semi, demi, and hemi, as semicircle, demitone, and hemisphere.
63. What does Sine signify?
Without, as sinecure.
64. What does Stereo signify?