the feeling of psychological strain and uneasiness produced by situations of danger, threat, and loss of personal security or by internal conflicts, frustrations, loss of self-esteem, and grief. Also called emotional tension.
the misperception that vertical lines are longer than horizontal lines when both are actually the same length. The vertical element of an upper case letter T, for example, looks longer than the cross bar, even when the lengths are identical. See also foreshortening; Helmholtz square illusion.