adjective Perpendicular to the vertical; parallel to the plane of the horizon; level, flat.
horizontal lines
adjective Relating to horizontal markets
adjective Pertaining to the horizon.
adjective Involving wines of the same vintages but from different wineries.
adjective Having the two notes sound successively.
adjective Relating to sexual intercourse.
horizontal tango
adjective Being or relating to the transmission of organisms between biotic and/or abiotic members of an ecosystem that are not in a parent-progeny relationship.
Infectious agents may spread by horizontal transmission.