nocio

Read it as one root and stop reading. Nocio invites a very tempting bad parse: no- looks like a negative and cio looks like ĉio, everything, so nocio reads for half a second as not-everything. It is nonsense. The negative in Esperanto is ne, never no; ĉio has a hat and this word does not; and nocio came in whole from Latin notio with nothing removed. Say no-TSI-o - the c is ts, so the word ends with the same sound as scienco.

Three words for what is in your head, and the differences are real.Ideo at rank 298 is the broadest and the most casual: a thought that occurred to you, a plan, a suggestion. Mi havas ideon is I have an idea. Koncepto at 1,923 is a formed and defined notion, the technical unit of thought that a philosopher or a designer works with. Nocio sits between them and leans towards the general category rather than the individual thought: la nocio de justeco, the notion of justice, is the concept as such and not anybody's particular version of it. It also carries the English idiom of a vague grasp - havi nocion pri io, to have some notion of something - which the other two do not.

How it behaves in a sentence. It takes de for what the notion is of and pri for the subject you have a notion about, and the distinction is not decorative: la nocio de libereco is the concept of freedom itself, while nocio pri libereco is some idea somebody holds concerning it. Difini nocion is to define a term, and this is the word a dictionary uses about its own entries.

Register. Abstract, slightly academic, entirely at home in the philosophical and scientific Esperanto that the movement wrote a great deal of. In everyday speech, use ideo.