Grammar Point
prefix
pref 
word usually written using kana alone
uk 
honorific or respectful (sonkeigo) language
hon 
polite (teineigo) language
pol 
humble (kenjougo) language
hum 
お

honorific/polite/humble prefix

usu. before a term with a kun-yomi reading; おん is more formal

お + Noun

The prefix お is used to add a layer of politeness, respect, or humility to a word. It is most commonly attached to words with Japanese origins (kun-yomi). It can be used to show respect to the listener's belongings or actions, or simply to make one's own speech sound more refined and elegant.

Polite Nouns

When added to common nouns, it makes the word sound more polite or refined. Some words, like 'tea' or 'money', almost always include this prefix in polite conversation.

Tea

Money

Alcohol / Sake

Honorific Nouns

When referring to things belonging to the person you are speaking to, adding お expresses respect toward that person.

Your name

Your country

Note

While お is typically used with words of Japanese origin, and ご is used for words of Chinese origin (on-yomi), there are exceptions where お is used with Chinese-origin words that have become very common in daily life (e.g., お電話, お料理). Using this prefix with words for things that are generally considered 'dirty' or 'negative' is usually avoided.

お + Verb ます stem

The prefix お can be combined with the ます stem of a verb to create honorific or humble expressions, showing respect for the person performing the action or humbling one's own actions in relation to a superior.

Honorific Verb Forms

Used to describe the actions of someone you want to show respect to, such as a teacher or a customer.

To wait (respectful)

To read (respectful)

Humble Verb Forms

Used when the speaker is performing an action for the benefit of someone of higher status.

To help (humble)

To send (humble)

Note

This construction is a part of formal Keigo (honorific speech). The humble form often follows the pattern 'お + ます stem + します', while the honorific form often follows 'お + ます stem + になります'.

お + Adjective

The prefix お can be added to certain adjectives to make the description sound more polite or to show respect when describing someone else's state or attributes.

い-Adjectives

Used to politely describe the state of the person you are talking to.

Busy (polite/respectful)

Early / Fast (polite/respectful)

Words: 
御お
御おん
Radicals of radicals