On; in contact with and supported by a surface.

Sobre; en contacto y sostenido por una superficie.

At the time of; immediately after; on the occasion of.

Al; en el momento de; inmediatamente después.

Onto or against; directed at or pressing on.

Sobre o contra; dirigido a o presionando.

About; concerning; with regard to (formal).

Sobre; acerca de; con respecto a (formal).

Affecting or directed at; impending upon or closing in.

Que afecta o se dirige a; inminente o encima.

Depending on; based on; using or by means of.

• In oaths or assurances: upon my word, upon my life.

Dependiendo de; basado en; mediante; por.

• En juramentos/aseveraciones: sobre mi palabra, sobre mi vida.