What is the meaning of -ra?

Allative singular suffix.

[with verbal noun] in order to

Forms nouns or adjectives, mostly from nominal stems.

third-person singular future of -re

used to make suggestions

Suffix forming adjectives from nouns.

Used to form the comparative degree of adjectives

Used to form the genitive plural of adjectives

onto, on

for, by

Collective suffix, attached to nouns or adjectives, used to form nouns: -ry, -y

Rōmaji transcription of ら

nominal suffix

first/third-person singular imperfect subjunctive

Source: wiktionary.org