ideologio

Ideologio is the organised set of ideas a party, a movement or a class holds about how society should work. It is ideo plus the international -logi- element that marks a field of study, and it lands in Esperanto looking exactly as it does in French, German, Russian and English - which is the whole point of the international vocabulary layer.

The word has an unusually well documented and unusually sour history. Destutt de Tracy coined idéologie in 1796 for what he intended as a rigorous science of where ideas come from. Napoleon then used idéologues as a term of abuse for intellectuals with theories and no grip on government, and it was the insult that travelled. Two centuries later the neutral sense survives in academic writing while the everyday sense still carries Napoleon's edge: an ideology is usually the rigid system somebody else has.

Register. This is an encyclopedic word and it wants encyclopedic company. It sits naturally beside kapitalismo, teorio and filozofio, and beside the historical vocabulary this chapter also carries. Write about ideologies factually and the word does its job; use it as a verdict and you are doing what Napoleon did.

The adjective is ideologia and a person who holds one is an ideologo, which is where the pattern rhymes with filozofo and biologo.