Fun words and terms from some of my interests:
Thermionic - valve amplification
Hysteresis - magnetics
Gaussian - magnetics
Reverberation constant - Acoustics problem solving term, along with reverberation times (say it fast a bunch of times)
Acoustician - One who does acoustic preparations prior to a recording session (one of my specialties was determining and correcting the causes of sonic colorations)
Circles of confusion - limits maximum resolution in any photographic reproduction process
Ballistic coefficient - Aerodynamics of a bullet (super-simplified) How well a bullet will cut through the air.
Sectional Density - A direct indication of the penetrating power of a bullet (mass/diameter2 of a projectile)
Angle of incidence - photography - lighting angles - Measured from a plane perpendicular to the axis of the receiving lens
Asplenium - Botany - Genus of ferns (Ferns are a special interest, inside a special interest)
Monocotyledons - Botany - Single flower leaf ( another word that sounds like your tongue is doing tai chi exercises)
Epiphytic - Horticulture - plant that grows on other plants, but not parasitic
Lithophytic - Horticulture - plant that grows on rocks
Angiosperm - Botany - flowering plant (try telling a receptionist that she has a number of angiosperms on her desk)
Zygomorphic - Botany - bi-laterally symmetrical (it's just hard to find a conversaton to drop this word into)
Phalaenopsis - Botany - Genus of orchids (want to talk about orchids, anyone?)
Thermionic, thermionic, thermionic!