(baseball) The motion of a sharply diving sinker pitch.

(sciences, countable) Any metal that has a specific gravity greater than about 5, especially one, such as lead, that is poisonous and may be a hazard in the environment.

(chemistry) Water containing deuterium instead of normal hydrogen (protium) (symbol D₂O); used as a moderator in nuclear reactors.

Deuterium.

having a high centre of gravity, and liable to topple / (of an organization) having an excessive number of administrators or managers

In a heavy-handed manner.

An alleged medical condition, described as an unpleasant sensation of pain and heaviness in the lower limbs.

(informal) Resembling or characteristic of heavy metal music.

A heavy optical glass, consisting essentially of potassium borosilicate.

(of horse racing) Going (i.e. conditions) that are wet and muddy (difficult to gallop on) / (idiomatic) Something that is boring; difficult to make progress on, or tedious