Notations that are mnemonic outside of English Some conventional math notations seem arbitrary to English speakers but were mnemonic to non-English speakers who started them. To give a simple example, Z is the symbol for integers because of the German word Zahl(en) 'number(s)'. What are some more examples?

Łukasiewicz notation for logic represents $\land \lor \leftrightarrow$ with the letters $K A E$ respectively, so that for example $r\lor(p\land q)$ is $ArKpq$.  $K A E$ are the initials of the Polish words koniunkcja, alternatywa, ekwiwalencja.
I don't know why Łukasiewicz used $C$ to represent material implication. 
