5. (Opt.)
Defn: An arrangement of two lenses for a microscope, designed to correct spherical aberration and chromatic dispersion, thus rendering the image of an object more clear and distinct. W. H. Wollaston.
6. pl. (See No. 1.)
Defn: Two dice, each of which, when thrown, has the same number of spots on the face lying uppermost; as, to throw doublets.
7. pl. Etym: [Cf. Pr. doblier, dobler draughtboard.]
Defn: A game somewhat like backgammon. Halliwell.
8. One of two or more words in the same language derived by different courses from the same original from; as, crypt and grot are doublets; also, guard and ward; yard and garden; abridge and abbreviate, etc.
DOUBLETHREADED
Dou"ble*thread`ed, a.
1. Consisting of two threads twisted together; using two threads.
2. (Mech.)