verb

• (transitive, archaic) To distinguish, to make noteworthy.
  "[…] God has planted in man a ſenſe of ambition, and a ſatisfaction ariſing from the contemplation of his excelling his fellows in ſomething deemed valuable amongſt them. It is this paſſion that drives men to all the ways we ſee in uſe of ſignalizing themſelves, and that tends to make whatever excites in a man the idea of this diſtinction ſo very pleaſant."
• (transitive, archaic) To display or make known (an attribute, quality, etc.); to call attention to.
  "[T]he great Creator hath likevviſe ſignalized his Care and Skill, by giving Animals an architectonick Faculty, to build themſelves convenient places of Retirement, in vvhich to repoſe and ſecure themſelves, and to nurſe up their Young."
• (transitive, archaic) To point out; to take special note of.
  "This expression rex Anglorum is rightly signalised by historians as a milestone in our history."
• (transitive, chiefly nautical) To communicate with (someone) by means of a signal.
  "a ship signalizes its consort"