tractrix, tractor

[Lat. tractor i us, pertaining to drawing; Fr.tractoire, tract rice, from Lat. tractus, pa. par. of traho to draw.] Math . A curve whose tangent is always equal to a given line. It may be described by a small weight attached to a string, the end which moved along a given straight line or curve. The evolute of this curve is the common catenary. trāde, *tred, *trod, s. & a. [Originally a path trodden, from Á. S. tredan =to tread (q.v.).] A. As substantive: *1. A path, a pa age, a way. "A postern with a blinde wicket there was, A common trade to pa e through Priam's house." Surrey: Virgil's Anis , ii. 593. *2. A track, a trace, a trail. (See extract under TRACT, v. (1), 2.) *3. Way, course, path. "The Jewes, emong whom alone and no moe, God hitherto semed for to reigne, by reason of their knowl. edge of the law, and of the autoritee of being in the right trade of religion."- Udall: Luke xix. *4. Frequent resort and intercourse; resort. "Some way of common trade." 4143 interests. made at the Patent office, Washington. The fee is $25 for a trade-mark, and $5 for a label. The use of a label when not registered becomes the right of the person who first used it and made it of value. [WATERMARK.]