expression
because of; due to; on account of
Formal or written expression indicating reason or cause. Often used in notices, announcements, and formal explanations.
本日は祝日に付き、休業させていただきます。
We are closed today due to the public holiday.
工事中に付き、ご迷惑をおかけします。
We apologize for the inconvenience due to construction work.
expression
Formal equivalent of について. Used in written language or formal speech to indicate a topic.
See also: について
この件に付き、ご質問があればお知らせください。
If you have any questions regarding this matter, please let us know.
expression
per; for every
Used to express a rate or proportion, similar to について in its distributive sense. Common in formal or business contexts.
See also: について
参加者一名に付き、資料を一部お渡しします。
We will provide one set of materials per participant.
について is the standard, neutral way to say 'about' or 'regarding'. に付き is a more formal, written variant, and also carries the additional meanings of 'because of' and 'per'.
Derived from the verb 付く (つく, 'to be attached') in its continuative form 付き, combined with the particle に. The expression developed from the idea of 'being attached to' a reason or topic, giving rise to the formal usages 'because of', 'regarding', and 'per'.