Tautology - Unnecessary repetition, usually in close proximity, of the same word, phrase, idea, argument, etc. The saying of the same thing twice in different words generally considered to be a fault of style (OED) although it can be used as a literary device.
"PIN number" is tautologous - it repeats "number" next to the initial N, which means "number".
"My PIN number that I use to identify my card with is on this piece of paper" - that I use to identify my card with is also tautologous.
When 'the same thing' is repeated in different languages (eg the examples in the OP) - Loch Ness Lake, La Brea Tar Pits, Drankensberg Mountains, Schwarzwald Forest - or, involves unfamiliar jargon - DVD disk, ISBN number - the tautology may not be redundant (superfluous, excessive; surplus; unnecessary (OED)), but in fact necessary for clarity (until such time as speaker and spoken-to can understand the unfamiliar language).
Tautology is a kind of pleonasm which is when more words are used in a sentence or clause than are necessary for clear expression (either as a fault of style, or as a rhetorical figure used for emphasis or clarity). For example,
Jill saw the building burning down with her own eyes. (She must have seen it with her own eyes).
The vote was completely and totally unanimous. (A unanimous vote cannot be anything but complete and total).
Although tautology and pleonasm are closely related, they are not synonyms. A tautology is a kind of pleonasm by definition. The reverse is not the case.
(Note that this answer refers to tautology in its original, rhetorical sense. In the early twentieth century philosophers Bertrand Russell and Ludwig Wittgenstein used the term tautology to describe a formula of the propositional calculus which is true under every assignment of truth or falsehood to its propositional letters, for example ‘If p and q then p’. In this context it is also used more widely to describe any proposition which is true because of its logical form rather than its content (OED)).