alone (Adjective) — Isolated from others. ex. "could be alone in a crowded room" ex. "was alone with her thoughts" ex. "I want to be alone"
alone (Adjective) — Lacking companions or companionship. ex. "he was alone when we met him" ex. "she is alone much of the time"
alone (Adjective) — Exclusive of anyone or anything else. ex. "she alone believed him" ex. "cannot live by bread alone"
alone (Adjective) — Radically distinctive and without equal. ex. "he is alone in the field of microbiology" ex. "this theory is altogether alone in its penetration of the problem"
alone (Adverb) — Without any others being included or involved. ex. "the burden of proof rests on the prosecution alone"
alone (Adverb) — Without anybody else or anything else. ex. "the child stayed home alone" ex. "the pillar stood alone, supporting nothing"