If you want to be fancy you can say "birthday extravaganza" this means a large and put together event or party. You can use it as a cheeky way to say birthday celebration while sounding a little fancy :)
Most of the time when talking about a social event centred around someone's birthday we would call this a 'Birthday party', however you could use any of the answers when perhaps inviting someone, or telling someone about a past party. For example - "Would you like to come to my birthday get-together?" or "We are having a birthday celebration for my son's first birthday. We'd love for you to come."
人の誕生日を中心とした社交行事について話す時大抵の場合は、 'Birthday party'と呼びますが、恐らく人を招待する時又は過去のパーティーについて話す時、いずれの回答も使うことが出来ます。
例文
"Would you like to come to my birthday get-together?"
私の誕生日会に来てくれますか?
"We are having a birthday celebration for my son's first birthday. We'd love for you to come."
息子の1歳の誕生日のお祝いをします。あなたに是非来て欲しいです
When referring to a party then this can also be called 'bash' this is more of a casual informal term
A celebration is when people get together for a particular reason (to celebrate) so like christmas, birthdays, anniversaries etc
get together means people meeting up and enjoying each others company
To have a knees-up means to have a party, especially a lively party with dancing.
A 'bash' is a party or social event.
The principal celebration of someone's birthday would usually be a party.
"Are you going to Paul's birthday bash this evening?"
To have a knees-upは特にダンスをしたりするような賑やかなパーティーをすることです。
A 'bash'はパーティー又は 社交行事のことです。誕生日の主なお祝いは通常パーティーになります。
例文
"Are you going to Paul's birthday bash this evening?"
今晩のポールの誕生祝いに行くの?
1. "Celebration"
Celebration can be used when referring to parties that aren't birthdays. However, birthday parties are a type of celebration. It is slightly more vague than the second example sentence I have given due to the fact 'celebration' could refer to various different types of parties (e.g. work parties, family gatherings etc).
2. "Birthday gathering"
A 'gathering' is an event where a group of people come together. A 'birthday gathering' shows that people are coming together to celebrate a birthday.
Many times when we celebrate someone's birthday, we eat a meal with that person. You can say birthday breakfast, lunch, or dinner. Dinner is normally the most common.
I hope that this helps :)
Other phrases commonly used to refer to a birthday party are "birthday bash" or "birthday celebration".
For example, you can say:
-I am throwing myself a 30th birthday bash
-I am planning on having a very big birthday celebration this year.
"birthday party"(誕生日パーティー)を表す、その他のよく使われる表現には、"birthday bash" や "birthday celebration" があります。
例えば、次のように言うことが出来ます。
【例文】
-I am throwing myself a 30th birthday bash
(私の30歳の誕生日パーティーを開きます)
-I am planning on having a very big birthday celebration this year.
(今年は盛大な誕生日パーティーを開く予定です)