A distich is a pair of verse lines that stand together as a single unit, often forming a short stanza or complete thought. In classical poetry, the word is especially used for the elegiac couplet: one line of dactylic hexameter followed by one line of dactylic pentameter.
In modern usage, it can also mean any couplet, but the classical sense is the most specific and established.
A two line Greek stanza. The distich is particularly associated with Greek elegiac verse and consists of one line of dactylic hexameter and one line of dactylic pentameter.
Example
Morning light climbs the hill in a narrow gold stream,
Night loosens its grip and dissolves like a dream.