Let's break it down:
* Gaidscaoileadh: This is the Irish word for "dissemination" or "distribution." It's related to the verb "scaoileadh" meaning "to release."
* by: This is simply the English preposition "by."
* Mairtín Ó Direáin: This is the name of a well-known Irish poet and writer.
Therefore, "Gaidscaoileadh by Mairtín Ó Direáin" likely refers to the distribution or spread of something by Mairtín Ó Direáin, possibly his writings or ideas.
To understand the exact meaning, you would need more context. For example, what is the full title or text in which this phrase appears? Knowing the context will help you determine the precise meaning and purpose of the dissemination.