1) Classical mechanics 2) Kind of door or scale 3) Like glass doors, often 4) Like some doors or scales 5) Like some scales 6) Slippery 7) Slippy 1) Descending 2) Downward 3) Slippery 4) Slippy 
Rolling a finger off a hole to create a sliding pitch change.
[motion] Sliding is a type of frictional motion between two surfaces in contact. This can be contrasted to rolling motion. Both types of motion may occur in bearings. The relative motion or tendency toward such motion between two surfaces is resisted by friction. Friction may damage or `wear` the surfaces in contact. However, wear can be re...
• (a.) That slides or slips; gliding; moving smoothly. • (a.) Slippery; elusory.
(from the article `glacier`) Glaciers that are at the melting temperature at the base may also slide on the bed. Two mechanisms operate to permit sliding over a rough bed. First, ... The fastest glaciers (other than those in the act of surging) are thick, temperate glaciers in which high subglacial water pressures produce high ... [2...
Slid'ing adjective 1. That slides or slips; gliding; moving smoothly. 2. Slippery; elusory. [ Obsolete] « That sliding science hath me made so bare.» Chaucer. Sliding friction (Mech.) , 
[adj] - being a smooth continuous motion
adjective being a smooth continuous motion
The act of leaving one's check to assist a team mate.