Difference between Downstairs and Downstair

What is the difference between Downstairs and Downstair?

Downstairs as an adjective is a floor lower than the one a speaker currently occupies. while Downstair as an adjective is downstairs

Part of speech: adjective

Definition: A floor lower than the one a speaker currently occupies.

Part of speech: noun

Definition: The genitalia

Part of speech: adverb

Definition: living, stepping, or coming down the stairs

Example sentence: My schedule goes: wake up, running, exercise, downstairs, running shoes off, then to the shower. That's the Jackie Chan diary.

Part of speech: adjective

Definition: downstairs

We hope you now know whether to use Downstairs or Downstair in your sentence.