-æ|-iː|pl. suffix of L. nouns of 1st decl. in -a, and romanized form of Gr. -αι pl. of nouns in -ē, -a, -ēs, -as. Retained in Eng. in words not naturalized or merely in technical use, as alæ, laminæ, larvæ, nebulæ, striæ. Esp. in proper names of cl. antiquity, as Heraclidæ, and modern names of orders and families of animals and plants as Felidæ, Falconidæ, Geometridæ, Leguminosæ, Rosaceæ, Rosidæ, Roseæ. In other words it varies with the Eng. form in -as, as actiniæ or actinias; or is retained only in technical senses as mathematical formulæ, theological formulas. In all words thoroughly popularized it yields to -s, as in arenas, areas, auroras, hyænas, fuchsias, calceolarias, Floras, Faunas, Julias, Marias, Cleopatras, the two Americas.