Tic-Tac Escapement

Type of recoil escapement, the pallets of which embrace just one or two teeth of the escape wheel. Clocks Magazine.
Also:
A small anchor escapement which extends over only two teeth of the escape wheel. Used on French and some early English clocks with bob pendulums. Oldandsold.com.
The 'anchor' only embraces two or three teeth of the escape wheel. (hotantiquespro.com)
Type of recoil escapement, the pallets of which embrace just one or two teeth of the escape wheel. Clocks Magazine (website)
A form of anchor escapement in which the anchor only spans one to three teeth of the escape wheel. It is fitted to French drum clocks with short pendulums swinging through a large arc. Sometimes one pallet is formed to give frictional rest only, all the lift being on the other pallet. TermWiki
A small anchor escapement which extends over only two teeth of the escape wheel. Used on French and some early English clocks with bob pendulums. Oldandsold.com
A type of escapement found in some early clocks and a modified form of the anchor escapement. Helena Hayward (ed.). The Connoisseur's Handbook of Antique Collecting. Galahad Books, NY, 1960. 320 pp.
An escapement in which the pallets span but few teeth to effect a wide arc to the short, pivoted pendulum. Donald S. McNeil (ed.). Jewelers' Dictionary. Jewelers' Circular-Keystone (3rd) 1976