die Tischplatte
tabletop
The upper, flat, horizontal surface of a table, on which objects are placed.
Die neue Tischplatte aus massivem Eichenholz ist sehr robust.
The new tabletop made of solid oak is very sturdy.

tabletop
Loading your saved state.
tabletop
The upper, flat, horizontal surface of a table, on which objects are placed.
Die neue Tischplatte aus massivem Eichenholz ist sehr robust.
The new tabletop made of solid oak is very sturdy.

The word consists of 'Tisch' (table) and 'Platte' (slab/panel). A 'Platte' is a flat, often rectangular sheet or slab made of a solid material. The Tischplatte is therefore the upper, flat panel of a table.
Vorsicht, die Tischplatte ist aus Glas und sehr empfindlich.
Careful, the tabletop is made of glass and is very delicate.
The component '-platte' is very productive and refers to many kinds of flat surfaces. If you recognize this pattern, you can more easily understand other words such as 'Arbeitsplatte' (countertop/worktop, in the kitchen) or 'Holzplatte' (wooden board/panel).
Die neue Arbeitsplatte in der Küche ist aus Granit.
The new countertop in the kitchen is made of granite.
Common verbs in connection with a tabletop are 'abwischen' (to wipe down), 'reinigen' (to clean), or 'polieren' (to polish). Typical adjectives describe the material, e.g. 'hölzern' (wooden), 'gläsern' (glass), or 'massiv' (solid).
Könntest du bitte die Tischplatte nach dem Essen abwischen?
Could you please wipe down the tabletop after dinner?
surface
'die Oberfläche' and 'die Tischplatte' can both refer to the upper surface of a table. However, 'die Oberfläche' is more general and only describes the outer layer or visible side. 'die Tischplatte' is a specific part of a table: the flat top on which you place things. The words can be confused when talking about a table. If you mean the whole tabletop part, say 'Tischplatte'; if you are only talking about the texture or condition of the top, 'Oberfläche' fits.

Wir legen die Bücher auf die Tischplatte, damit der Boden frei bleibt.
We put the books on the tabletop so the floor stays clear.
Die Oberfläche des Tisches fühlt sich nach dem Ölen viel glatter an.
The surface of the table feels much smoother after oiling.