Sensu - Common Qualifiers

Common Qualifiers

Sensu is a Latin word meaning "in the sense of". It is the ablative case of the noun sensus, here meaning "sense". It is used in a number of fields including biology, geology, linguistics, semiotics, and law, often accompanied by an adjective (in the same case). Three such phrases are sensu stricto – "in the strict sense", abbreviation s.s.; sensu lato – "in the wide or broad sense", abbreviation s.l.; and sensu amplo – "in a relaxed, generous (or 'ample') sense", a similar meaning to sensu lato.

When appropriate, comparative and superlative adjectives may also be used to convey the meaning of "more" or "most". Thus sensu stricto becomes sensu strictiore ("in the stricter sense" or "more strictly speaking") and sensu strictissimo ("in the strictest sense" or "most strictly speaking").

Current definitions of the plant kingdom (Plantae) offer a biological example of when such phrases might be used. One definition of Plantae is that it consists of all green plants, all red algae and all glaucophyte algae. A stricter definition excludes the red and glaucophyte algae; the group defined in this way could be called Plantae sensu stricto. An even stricter definition excludes green algae, leaving only land plants; the group defined in this way could be called Plantae sensu strictissimo. Conversely, where convenient, some authors derive expressions such as "sensu non strictissimo", meaning "not in the narrowest possible sense".

Another common usage is to follow sensu by a person's name. Thus "sensu Smith" means "in the sense intended by or used by Smith".

Søren Kierkegaard uses the phrase sensu eminenti to mean "in the pre-eminent sense".

A similar form is in use to indicate the sense of a particular context, such as "Nonmonophyletic groups are ... nonnatural (sensu cladistics) in that..." or "...computation of a cladogram (sensu phenetics)..."