Genus der Substantive

English keeps gender for natural sex: "he" for a man, "she" for a woman, "it" for most things. Every Ukrainian noun, including a table or a cloud, is masculine, feminine or neuter. This is not about meaning; it is a grammatical class, and it decides the form of every adjective, past-tense verb and pronoun that goes with the noun.

Read the gender from the ending

In the dictionary form (the nominative singular), the ending is a strong clue:

Where the clue misleads

• Men ending in -о or -а. Тато "dad", дядько "uncle", Петро are masculine because they are men; Микола and Сава end in -а and are masculine too. Meaning wins here.
• Feminine nouns ending in a consonant. A group of feminines end in a soft sign or a consonant: ніч "night", сіль "salt", любов "love", осінь "autumn", радість "joy". The ending -ість is a reliable sign of a feminine noun.
• -я can be feminine or neuter. Земля, пісня "song" are feminine; ім'я, життя, щастя "happiness", теля "calf" are neuter. Neuter -я words often show a doubled consonant or an apostrophe before it.

For nouns ending in -ь there is no safe guess: день and олівець "pencil" are masculine, сіль and тінь "shadow" feminine. Learn these with an adjective attached: новий день, чорна сіль.

Why it matters straight away

Gender shows up in the words around the noun:

• Мій стіл новий. Він стояв у кухні. "My table is new. It stood in the kitchen."
• Моя книга нова. Вона лежала на столі. "My book is new. It was lying on the table."
• Моє вікно нове. Воно було відчинене. "My window is new. It was open."

The most useful habit is to learn every noun with мій / моя / моє in front of it. Also note that a word's gender can differ from its Russian cousin: Ukrainian біль "pain" is masculine, and so is собака "dog", despite its -а.