ojalá, interj., would to God...! used independently, would to God (it were so)!
ojo, m., eye; echar —s, to cast eyes.
oler, to smell, scent, discover.
olvidar, to forget.
olvido, m., forgetfulness, oblivion; dar al —, to forget, cast into oblivion.
once, eleven; las —, eleven o'clock.
operación, f., operation; gabinete de —es, operating-room; sillón de —es, operating-chair, dentist's chair.
operar, to operate, operate on.
opinar, to have an opinion, think; ¿opina usted? do you think so?
oponer, to oppose.