What is the meaning of Ellas?

they

pre-reform spelling (used until 1943 in Brazil and 1911 in Portugal) of elas

they f

they, them (used subjectively and after prepositions; can refer to women and feminine nouns)

Like other masculine words, masculine pronouns can be used when the gender of the subject is unknown or when the subject is plural and of mixed gender.

Treated as if it were third person for purposes of conjugation and reflexivity.

If le or les precedes lo, la, los, or las in a clause, it is replaced with se (e.g. se lo dije instead of *le lo dije).

Used primarily in Spain.

Only used in certain circumstances and rarely as a subject pronoun.

Source: wiktionary.org