Definition of titanium. : a silvery-gray light strong metallic element obtained from ilmenite and rutile and used especially in alloys and combined in refractory materials, pigments, and coatings â see element table.
Wiktionary(0.00 / 0 votes)Rate this definition: 1  roster(Noun) A list of names, usually for an organization of some kind such as military officers and enlisted personnel enrolled in a particular unit; a muster roll; or a sports team, with the names of players who are eligible to be placed in the lineup for a particular game.
MLB. 1  Active list - Also called the active roster, the 25-man is composed of 25 players who are playing for their Major League team. 2  Reserved list - Defined in Major League Rule 2, the 40-man roster is also known as the Major League Reserve List.