Solo (without an accent): Lonely, alone, without some one else. 'Estoy solo en casa' (I'm home alone). Sólo (with accent): Only, just. 'Sólo quiero estar en casa' (I just wanna be home). Único: unique, also can be translated as only in some cases. 'Una pieza única' (A unique piece). 'Es mi único amigo' (He's my only friend) Best regards, Alejo. REF.: I'm a Spanish Teacher.