A member of a ground-based army, of any rank. / (by extension, nonstandard) Any member of a military, regardless of specialty.

(intransitive) To continue steadfast; to keep striving. / (intransitive) To serve as a soldier.

(countable) One who lives alone, or in solitude; an anchorite, hermit or recluse. / (uncountable) Solitary confinement. / (uncountable) The state of being solitary; solitude

Living or being by oneself; alone; having no companion present / Performed, passed, or endured alone / Not much visited or frequented; remote from society

(archaic) The Rodrigues solitaire (Pezophaps solitaria), an extinct flightless bird.

(philosophy) The idea that the self is all that exists or that can be proven to exist. / Self-absorption, an unawareness of the views or needs of others; self-centeredness; egoism.

(astronomy) Any of the large eruptions of luminous hydrogen gas that rise thousands of kilometers above the chromosphere of the Sun.

(astronomy) The moment when the Earth is in that point of its orbit where the northern or southern hemisphere is most inclined away from the sun.

(astronomy) The moment when the Earth is in that point of its orbit where the northern or southern hemisphere is most inclined toward the sun.

(music) A piece of music for one performer. / A job or performance done by one person alone. / (games) A card game similar to whist in which each player plays against the others in turn without a partner