The Oxford English Dictionary defines "missional" as "Relating to or connected with a religious mission; missionary." In contemporary usage "missional" is an adjectival alternative to "missionary." Although both words are related to "missio" (Latin: sending), some scholars, including Darrell Guder et. al. in The Missional Church believe "missional" focuses on the the Church's indigenous, rather than cross-cultural context, with the church contextualizing its methods, morality, and message to fit this indigenous culture.
In this usage "missional" has rapidly entered the lexicon of the growing emerging church movement whose participants have popularized the term, enabling participants in this movement to recognize each other across denominational lines.