hy·dron·ic 
(hī-drŏnĭk)
(hī-drŏnĭk)adj.
Of or relating to a heating or cooling system that transfers heat by circulating a fluid through a closed system of pipes.
[HYDR(O)- + -onic (as in ELECTRONIC).]
- universalness
- Universal Product Code
- universal recipient
- universal resource locator
- universal set
- universal time
- universal Turing machine
- universe
- universe of discourse
- university
- univocal
- univocally
- Unix
- unjoint
- unjust
- unjustifiable
- unjustifiably
- unjustly
- unjustness
- unkempt
- unkennel
- unkept
- unkind
- unkindliness
- unkindly