1. (particle) away - indicates direction away from speaker, or from the person (or thing) who is the focus of the utterance. Also indicates onwards following verbs of motion. Like the other three directional particles, mai, iho and ake, it always follows manner particles (i.e. kau, kē, noa, rawa and tonu) if they are present in the phrase.
Tīkina atu he tūru mōku! / Fetch me a chair, please!
Titiro tonu atu ana ōna kaumātua ki te whakamahi i ōna kaha ki te kōrero, me tōna pai ki te whakatau i ngā whakahaere i waenga i a ia me ngā āpiha Pākehā a te kāwanatanga. (TTR 1994:73). / His elders were continually observing his ability in speaking and dealing successfully with the Pākehā officials of the government.
(Te Kākano Textbook (Ed. 2): 27, 120;)
2. (particle) away, in a direction away - used with verbs which designate perception or attitude.
Kātahi au ka titiro i taku ringaringa, ka kite au e heke ana te toto. Ngoikore tonu atu au. / Then I looked at my hand and saw that it was bleeding. I became quite faint.
3. (particle) other, others, next but one, before last, beyond that - when used following tērā and ērā in time expressions. When speaking of future events, atu is used to indicate a time further into the future than that just referred to or about to be referred to.
Ā tērā atu wiki haere ai mātou ki Heretaunga. / The week after next we travel to Hastings.
Kei Tāmaki-makau-rau rāua i te rā nei. Hei tētahi rangi atu, ka tae ki Te Kauwhata. E rua rangi atu, kei Rotorua. / They are in Auckland today. The next day they arrive in Te Kauwhata. They're in Rotorua in two days time.
4. (particle) Used when comparing things. This includes iti, although it may often be followed by iho.
He roa atu te whiore o te kau i tō te poaka. / A cow's tail is longer than that of a pig.
He iti atu te kapa kotahi ki te pereiti mā ngā minita, i te rau pauna a te tangata hei ako i tana tamaiti i ngā kāreti nunui (TKO 30/4/1920:9). / One penny in the plate for the ministers is smaller than a person's hundred pounds to teach his child in the large colleges.
(Te Kākano Textbook (Ed. 2): 101;)
5. (particle) Used with a verb repeated with mai to indicate reciprocal action.
Tū atu ana, tū mai ana rāua i tētahi taha o te awakeri. / They stood facing each other beside the ditch.
6. (particle) further - used to emphasise distance.
Kei tua atu ia i a Hine. / She is beyond Hine.
Te āhua nei kei waho iti atu o Kaiwaka tō rātou tawhiti ki waho (JPS 1957:230). / It would seem that their position was a little further out from Kaiwaka.
(Te Pihinga Textbook (Ed. 2): 45;)
7. (particle) other, another, some other, someone else - especially in the phrase tētahi atu.
Homai tētahi atu pune! / Pass me another spoon, please.
Tokowhā ngā kaiako, ā, i tēnei tau kua whiwhi te kura i tētahi atu. / There were four teachers and this year the school has another one.
8. (particle) including - when referring to different kinds of people or things using nouns followed by atu but without a determiner.
I hīkoi atu te tira ki Maungapōhatu, koroua atu, kuia atu, pakeke atu, tamariki atu. / The travelling party walked to Maungapōhatu, including elderly men, elderly women, adults and children.
(Te Māhuri Textbook (Ed. 2): 97;)
9. (particle) Used in time expressions, seemingly for emphasis.
Nō mua atu tēnei aituā i te Pakanga Tuatahi o te Ao. / This disaster was before the First World War.
(Te Kākano Textbook (Ed. 2): 121;)
10. (particle) apart from, other than, aside from, other, others - followed by i. Also used to indicate things that are additional to those already mentioned.
Atu i a koe, kārekau aku hoa. / Apart from you, I have no friends.
E whā i mate, e waru atu i taotū. / Four died and eight were wounded.