sektoro

The seam that is not there, and this one is unusually convincing. Sektoro ends in -or-, and a learner who has met traktoro, motoro and doktoro might reasonably guess that -or- is Esperanto's agent suffix, making sektoro the one who does sekti. It is not. Esperanto has no -or- suffix at all: the agent endings are -ist- for the trade and -ant- for the doer, which is how ŝuldanto is built eleven ranks earlier in this band. The -or in sektoro is fossil Latin, the agent ending of sector, and it arrived glued on. Treat the word as one root.

Where it really comes from, and who its relatives are. Latin secare is to cut. Sector is the cutter, the thing that divides. The word entered modern languages through geometry - the sector of a circle is the wedge you cut between two radii - and slid outward to mean any division of a larger whole: an economy, a city under occupation, a disk. In Esperanto its nearest cousin is sekcio at rank 2,105, from the same secare, and the distinction between them is worth keeping. A sekcio is a section of a document, an organisation or a body - a named subdivision on a plan. A sektoro is a broad field of activity or a wedge of territory.

The collocations you will actually meet. La publika sektoro and la privata sektoro are the standard pair; la agrikultura sektoro, la industria sektoro and la financa sektoro divide up an ekonomio. Beside them, parto is the general word for a part and does none of this work, and branĉo is what an organisation has.

Pronunciation and shape. Three syllables, sek-TO-ro, stress on the penultimate. The plural and accusative behave normally: sektoroj, sektoron, sektorojn. The adjective sektora exists and is dull but useful.