If that's your definition, then effectively the entire planet is zionist, including almost all Arab states, and even the PLO.

Are you asserting that Egypt is zionist? The Palatinian Liberation Organization? All of there states have said that Israel has a right to exist. Passed resolutions.

If so, then what value has the word?

Zionism has changed over time. Israel exists, is going no where, and only weirdos think Israel should vanish.

However many will espouse an end to zionism today, which typically and effectively means no more expansion into modern Palastine, and a 2 state solution.