olemus
(1a) kandevahend tavalises tähenduses
Wiktionary:
1. a small, typically rectangular or round, flat, and rigid object upon which things are carried.
https://en.wikipedia.org/wiki/Tray

(1b) liikuv disketi, plaadi või kasseti sööte seadis
Wiktionary:
3. a component of a device into which an item is placed for use in the device's operations
https://duckduckgo.com/?q=%22CD+tray%22&t=h_&iar=images&iax=images&ia=images

(1c) ikooni- ja teateala kasutajaliideses
Wiktionary:
4. (computing, graphical user interface, informal) a notification area used for icons and alerts
https://docs.oracle.com/javase/tutorial/uiswing/misc/systemtray.html