1. Pointing out or identifying the preposed, absolute, or appositional noun, noun phrase or pronoun which follows it. Never followed by the proper article.
Ko Tangi te metua o tērā tamaiti.
Tangi is the father of that child;
Ko Tangi, ‘e tangata kino ‘aia.
Tangi, he is a wicked man;
Ko ‘ai koe?
Who are you?;
Ko tērā te ‘are toa.
That’s the shop, there’s the shop;
Ko te vairākau tēia ‘ei rapakau i tō‘ou maki.
This is the medicine for treating your complaint;
Ko te ‘openga tēia i tā tātou tāmataora.
This is the end of our show;
Ko māua ko Tangi i ‘aere ei ki te ‘āpi‘i.
Tangi and I walked to school;
Kua kite mātou ko Pōvaru mā i te pa‘ī i te tere‘anga mai.
Pōvaru and the rest of us saw the ship coming in;
Kua ‘aere mai ‘a Pā rāua ko Tere.
Pā and Tere have come;
Ko Tara, ko Tū tē ‘aere maī ra.
It’s Tara and Tere coming.
2. Ko te, lest, in case, for fear that (where te introduces a sentence nominalisation); often used with ā‘ea or ākonei perhaps.
Kua mataku ‘aia ko te ta‘uri te poti.
He was afraid (lest) the boat might capsize;
E tāpeka koe i te moni ki roto i te ‘ōrei, ko te ngaro ākonei.
Tie the money up in the handkerchief in case it gets lost;
E ‘apai koe i te pereue ua pēnei ‘ua ake ko te ua mai.
Take a raincoat in case it rains;
E tāpeka koe i tō‘ou ‘oro‘enua, ko te ‘aere ākonei ko te kai i te meika ā te tangata.
Tie up your horse in case it goes and eats the people’s bananas;
E ‘aere ngāko‘iko‘i kōtou, ko te tūrēti kōtou ākonei i te ‘āpi‘i.
Hurry along or you‘ll be late for school. (See ko‘ai, koia.) [Pn. *ko.]