tach·o·cline 
(tăkə-klīn′)
(tăkə-klīn′)n.
The boundary in the solar interior between the outer convection zone and the inner radiative zone. This boundary arises from the fact that the convection zone rotates faster near the solar equator than it does near the solar poles, while the interior of the sun rotates equally at all latitudes.
[Greek takhos, speed + -CLINE.]
- out of sight
- out of sorts
- out of square
- out-of-state
- out-of-stater
- out of step
- out of stock
- out of the blocks
- out of the blue
- out of the chute
- out of the loop
- out of the question
- out of the running
- out-of-the-way
- out of the way
- out of the woods
- out of the woodwork
- out of this world
- out-of-touch
- out of touch
- out-of-town
- out-of-towner
- out of turn
- out of wedlock
- out of whack