Keyway

Adventures in Logophilia, Day 159:

keyway

Simply, a keyway is the groove or channel for a key, especially in a lock requiring a flat metal key.

Threshold

Adventures in Logophilia, Day 158:

threshold

This noun has a few interesting facets:

1.) a section of wood or stone that lies under a doorway;

2.) a means or place of entry, or a place at the beginning of something;

3.) the point or level at which a physical or mental effect begins to be produced, as in "pain threshold": at which level do you begin to feel it?

According to Oxford Dictionaries, threshold is an Old English word - thresh being related to tread in a Germanic sense, and hold (perhaps) emphasizing "place to tread." This leads me to believe that the naming of Thresh in The Hunger Games was not entirely coincidental.  In fact, it probably wasn't.

To Osculate

Adventures in Logophilia, Day 157:

osculate (v)

To kiss (mathematically).  This is a geometry term used when a pair of curves or surfaces touch on a common tangent.  Using the word as "kiss" has a humorous context, but I'd imagine it would be perfect to describe two science scholars in love.