-tactic adj combining form having a specified kind of pattern or arrangement or having an orientation determined by a specified force: syndiotactic; phototactic. [from Greek taktikos relating to order or arrangement; see tactics]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014tac?tic (?tæk t?k) n. 1. tactics (def. 1). 2. a system or a detail of tactics. 3. a plan, procedure, or expedient for promoting a desired end. adj. 4. of or pertaining to arrangement or order; tactical. [1560?70;