Source: cirosantilli/nabla-symbol

= Nabla symbol
{tag=Mathematical symbol that looks like a Greek letter but isn't}
{title2=$\nabla$}
{wiki}

= Nabla
{synonym}

As if <Greek letters> weren't enough, <physicists> and <mathematicians> also like to make up tons of symbols, <mathematical symbol that looks like a Greek letter but isn't>[some of which look like the could actually be Greek letters]!

Nabla is one of those: it was completely made up in modern times, and just happens to look like an inverted upper case <delta (letter)> to make things even more confusing!

Nabla means "harp" in Greek, which looks like the symbol.