(moon): In general usage,kuu is spelled with a lower-case k when referring to the Earth's moon, as inTaivaalla loistaa kuu.(“The moon is shining in the sky.”). In astronomy, it is spelled with a capital K when referring to Earth'sMoon and with a lowercase k when referring to a satellite in general.
(month):kuu is used for "month" when a calendar month is referred to without naming it, e.g.viime kuussa(“last month”),ensi kuun aikana(“within next month”),100 euroa kuussa(“100 euro per month”). Note that the inessive case is used when talking about e.g. events that happened on that month, yet the external locative cases are used when talking about e.g. postponing events to next month (ensikuulle). The wordkuukausi is more commonly used for a month as a unit of time, butkuu can in some cases be used in that sense as well:kahden kuukauden loma(“a two months' vacation”),viisikuinen vauva(“a baby of five months”).
“kuu”, inKielitoimiston sanakirja [Dictionary of Contemporary Finnish][1] (in Finnish) (online dictionary, continuously updated), Kotimaisten kielten keskuksen verkkojulkaisuja 35, Helsinki:Kotimaisten kielten tutkimuskeskus (Institute for the Languages of Finland),2004–, retrieved1 July 2023
1) obsolete *) theaccusative corresponds with either thegenitive (sg) ornominative (pl) **) thecomitative is formed by adding the suffix-ka? or-kä? to thegenitive.
Fedor Tumansky (1790), “ку”, inОпытъ повѣствованїя о дѣянїях, положенїи, состоянїи и раздѣленїи Санкт-Петербургской губернїи [An experiment of an account of the acts, location, condition and division of the Saint Petersburg gubernia],Краткїй словарь ижерскаго, финскаго, эстонскаго, чюдскаго, и ямскаго нарѣчїя съ россїйскимъ переводомъ [A short dictionary of the Ingrian, Finnish, Estonian, Chud and Yamtian dialects with a Russian translation], page699
V. I. Junus (1936),Iƶoran Keelen Grammatikka[2], Leningrad: Riikin Ucebno-pedagogiceskoi Izdateljstva, page 9
Ruben E. Nirvi (1971),Inkeroismurteiden Sanakirja, Helsinki: Suomalais-Ugrilainen Seura, page225
Olga I. Konkova; Nikita A. Dyachkov (2014),Inkeroin Keel: Пособие по Ижорскому Языку[3],→ISBN, page72
*) theaccusative corresponds with either thegenitive (sg) ornominative (pl) **) theterminative is formed by adding the suffix-ssaa to the shortillative (sg) or thegenitive. ***) thecomitative is formed by adding the suffix-ka to thegenitive.