Definition of lineswoman in US English:

lineswoman

noun

Tennis Sport
  • In games played on a field or court: a female official who assists the referee or umpire from the sideline or touchline, especially in deciding on whether the ball is out of play.

Origin

Early 20th century; earliest use found in The Boston Globe. From the genitive of line + woman, after linesman.

Pronunciation

lineswoman

/ˈlʌɪnzwʊmən/