이고: And — Listing Nouns in Careful Register

이고 lists nouns as equals: 사과이고 배이고 — both in, same standing.

Gloss: and — listing in the written register. 우리말샘 이고: after batchim nouns, often in …이고 …이고, joining items with the same standing; 간에 may follow for a “whether A or B” flavour. The teaching gloss adds register colour; the particle entry itself is about equal listing.

What it does — measured lists

You are not explaining because. You are lining up nouns as co-members of a set.

사과이고 배이고 다 있어요.
학생이고 직장인이고 오세요.
빨강이고 파랑이고 상관없어요.
고기이고 채소이고 준비했어요.

Shopping and ingredients:

파이고 마늘이고 넣으세요.
고추이고 양파이고 썰어 두었어요.

The double …이고 …이고 frame is part of how the pattern feels — not a one-off 이고 stranded on a single noun without a list partner.

Noun list vs verb -고 vs spoken and

사과하고 배 사요.           casual
사과이고 배이고 사요.       listed, measured
씻고 잘라요.               verb sequence — different seat

우리말샘 highlights batchim nouns for 이고. Open-syllable nouns often take other listing habits — follow what you hear rather than forcing 이고 everywhere.

When to use — and when 하고 is better

Use 이고 when a careful list should sound even-handed (both options, both roles, both colours).

Prefer 하고 / (이)랑 in banmal chats and quick shopping talk.

Never put 이고 on verbs as if it were -고 (먹이고… as “and eat” is the wrong seat).

Practice rule: if you are listing nouns as equals and the sentence should feel measured, 이고 fits. If you are just chatting and, reach for 과/와, 하고 first.