Projectile comes from New Latin projectilis, from Latin proiectus, past participle of proicere ('to throw forth'), from pro- ('forth') + iacere ('to throw'). The historical chain includes Latin proiectus, Latin iacere, and Proto-Indo-European *yeh₁-. The quoted older senses, "to throw forth", "forth", and "to throw", supply the semantic anchors for projectile. The formation is best read as compound, participial, and borrowed: the word projectile carries its older form-history into a compact English lexical shape. In present English it is used as a noun, "an object propelled through the air, especially as a weapon". Related English forms include project, projection, projector, eject, and inject. The result is a noun and adj whose etymology preserves both the older form and the later English specialization.