This is the 8739th most frequent Spanish word.
solá
"Solá" is the feminine form of "solo" in Spanish, meaning "alone" or "by herself."
In this sentence, "solá" is used as an adjective describing how María remains, referring to the state of being alone (feminine form).
María se quedó solá en casa.
Maria stayed alone at home.
Here, "solá" is an adjective describing the chair's condition of being by itself (feminine object).
La silla está solá en el rincón.
The chair is alone in the corner.
In this context, "solá" refers to the individual decision of the feminine subject to act independently.