das Pad
tablet
Colloquial short form for a tablet computer.
Er liest seine E-Mails morgens immer auf dem Pad.
He always reads his emails on the tablet in the morning.

pad / tablet
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tablet
Colloquial short form for a tablet computer.
Er liest seine E-Mails morgens immer auf dem Pad.
He always reads his emails on the tablet in the morning.

'Pad' is a word from English and is pronounced similarly. It has taken on several meanings in German.
Kannst du mir mal das Pad geben? Ich möchte etwas nachschauen.
Can you give me the tablet for a second? I want to look something up.
In English, 'pad' can also colloquially mean an apartment ('my pad'). The word does not have this meaning in German.
Er hat sich für seine Notizen ein neues Pad gekauft.
He bought himself a new notepad for his notes.
You can recognize the meaning of 'Pad' from context. If it is about technology and screens, a tablet is meant. If it is about cosmetics or computer accessories, a pad or surface is meant. If it is about writing, a notepad is meant.
Sie surft am liebsten mit ihrem Pad auf dem Sofa.
She prefers browsing the internet on her tablet on the sofa.
Using 'Pad' for a tablet computer is mainly colloquial. In more formal contexts or in advertising, 'Tablet' or 'Tablet-Computer' is usually used.
Ich schaue mir abends im Bett gerne Serien auf dem Pad an.
I like watching series on the tablet in bed in the evening.
In the meaning of 'Unterlage' (surface/pad), 'Pad' is often the second part of a compound word. Examples are 'Mousepad' (mouse pad), 'Wattepad' (cotton pad), or 'Stempelpad' (ink pad).
Zum Entfernen von Make-up benutzt sie immer Wattepads.
She always uses cotton pads to remove makeup.
documents / mat
'die Unterlage' and 'das Pad' can both mean a flat object that lies under something or is used for something. 'Unterlage' is the more general German word and works for many materials and purposes, for example to protect a table or as a stable surface. 'Pad' is usually smaller and often softer; it is often used in fixed expressions like 'Mousepad' (mouse pad) or 'Wattepad' (cotton pad). Learners may confuse the words because a 'Pad' is often also a kind of 'Unterlage'. When speaking generally about something that lies under something else, 'Unterlage' is more natural. For small, specific products, 'Pad' sounds more normal.

Für die Computermaus kauft Lena ein neues Pad.
Lena buys a new pad for the computer mouse.
Vor dem Basteln legt Tom eine Unterlage auf den Küchentisch.
Before doing crafts, Tom puts a mat on the kitchen table.