solus

UK: /ˈsəʊləs/ US: (sô′lŏŏs; Eng. sō′ləs)

WordReference Random House Unabridged Dictionary of American English © 2025

so•lus  (sô′lŏŏs; Eng. sō′ləs), adj. [Latin.]

1. Foreign Terms (referring to a man) alone;
   by oneself (used formerly in stage directions). Cf. sola. 

Collins Concise English Dictionary © HarperCollins Publishers::

solus / ˈsəʊləs/ adjective

1. alone; separate
2. of or denoting the position of an advertising poster or press advertisement that is separated from competing advertisements: a solus position
3. of or denoting a retail outlet, such as a petrol station, that sells the products of one company exclusively: a solus site
4. (sola) alone; by oneself (formerly used in stage directions)

Etymology: 17th Century: from Latin sōlus alone