chron·o·scope 
(krŏnə-skōp′, krōnə-)
(krŏnə-skōp′, krōnə-)n.
An optical instrument for the precise measurement of very small time intervals.
chron′o·scopic (-skŏpĭk) adj.
- hear things
- hearth money
- hearthrug
- hearthstone
- heartily
- heartiness
- heartland
- heartless
- heartlessly
- heartlessness
- heart-lung machine
- heart massage
- heart of palm
- heart rate
- heart-rending
- heartrending
- Heart River
- heart-searching
- heartsease
- heart's-ease
- heartsick
- heartsickness
- heart-stricken
- heartstring
- heart-struck