arms race

arms race (plural arms races)

1. A competition for military supremacy between two powers, especially for the most weapons and the best military technology.
2. (figuratively) Any similar competition that involves competing developments.
   • 2006, R.M. Kilner, “The evolution of egg colour and patterning in birds”, in Biological Reviews, volume 81, page 389, column 1:

     The cost of parasitism has provoked an evolutionary arms race between parasite and host, in which hosts evolve defences to avoid becoming victimized and parasites counterattack by evolving strategies to outwit their hosts.