A bipolar cell.
"The scientist studied how light signals travel through a bipolar cell in the retina before reaching the brain."
of or relating to manic depressive illness
"Her friend suggested she visit a psychiatrist because her mood swings seemed symptomatic of bipolar disorder."
of, pertaining to, or occurring in both polar regions
"the bipolar distribution of certain species"
having two poles
"The compass needle points to both geographic north and south because it is a special bipolar instrument designed for dual-axis measurements."
Involving or having both extremes or poles at the same time.
"The debate became bipolar as arguments swung violently between total support and complete rejection without any middle ground."
In plain English: Bipolar describes someone who has extreme mood swings that flip between very high energy and deep sadness.
"The mood swings he experienced after his diagnosis were described by doctors as truly bipolar."
Usage: In medical contexts, this adjective specifically refers to bipolar disorder and should not be used as a casual synonym for "having two sides." When describing non-clinical situations with opposing qualities, prefer terms like "dual-natured" or "contradictory" to avoid confusion.
The word bipolar comes from combining the prefix bi- meaning "two" with polar, referring to having two poles or opposite ends. It entered English as a direct formation of these elements rather than evolving from an earlier single term.