The cardinal number immediately following thirty-eight and preceding forty.

(uncountable) A method of spacecraft propulsion (electric propulsion) that provides thrust by heating a (typically non-reactive) fluid. / (countable) A spacecraft that uses such method of propulsion.

(fandom slang) The ship of characters Katsuki Bakugou and Izuku Deku Midoriya from the My Hero Academia series.

Alternative form of rotary dial