similis

Similis, simile is a third declension adjective of two terminations: one form for masculine and feminine, simile for the neuter, ablative singular simili, genitive plural similium, neuter plural similia.

The case it governs is where the marks are won or lost. Classical Latin prefers the genitive for close likeness, especially of character - similis patris, "the image of his father" - and the dative for likeness in a general or external way, similis patri. Cicero keeps the distinction; later and ecclesiastical Latin uses the dative for both, and this corpus follows the later habit. Comparative similior, superlative the irregular simillimus. From it: similitudo, simulo, simulacrum, and English similar, simile, assimilate, simulate, resemble and the "similar triangles" of school geometry.