涯 is a bound form (b.f.) meaning 'boundary, limit, edge' — it cannot stand alone as a word. You'll find it in literary or formal compounds like 天涯 ('end of the sky; faraway place'), 生涯 ('career; livelihood', literally 'life's boundary'), and 无涯 ('boundless, limitless'). It carries a sense of a spatial or temporal limit, often with a poetic or abstract tone.