hour·glass 
(ourglăs′)
(ourglăs′)n.
An instrument for measuring time, consisting of two glass chambers connected by a narrow neck and containing a quantity of sand, mercury, or another flowing substance that trickles from the upper chamber to the lower in a fixed amount of time, often one hour.
adj.
Shaped like an hourglass: an hourglass design; an hourglass figure.
- fall for
- fall foul
- fall foul/afoul
- fall from grace
- fall guy
- fallibility
- fallible
- fallibleness
- fallibly
- fall in
- falling action
- falling-out
- falling rhythm
- falling star
- falling tide
- fall into line
- fall in with
- fall line
- fall off
- falloff
- fall on
- fall on deaf ears
- fall on (or upon)
- fallopian tube
- Fallot's tetralogy