Geogrammar

Retta Whinnery

Borrowed Latin Terms

English borrowed many Latin terms whose plurals cause problems. Singular Latin nouns ending with -um are made plural by changing the ending to -a, such as memorandum (sing.), memoranda (pl.). We imported some words in both singular and plural form but adopted others in only one form and created a new counterpart. Take agenda, for example. When it first arrived in the early 17th century, agenda was plural for agendum.

By the late 19th century, we'd made agenda singular and created a new plural, agendas, to make up for the loss of the original borrowing. Similarly, geological terms have eroded over time.

Singular

Plural

Comments

alluvium alluviums
alluvia
A deposit of silt or silty laid down during flooding. OED says the plural is rarely used; discussions with local geologists suggest this is because they use the singular as a mass noun.
datum
data
data, datums
data
AGI's Dictionary of Geological Terms lists datums as the plural for reference points and says data is a collection of statistics. Random House states data is the plural for reference points, and that data may be used as singular to mean information.
diluvium diluvia
diluviums
An archaic term once applied to widespread surficial deposits believed to be produced by vast floods, now known to be mostly glacial drift.
eluvium

Debris formed in situ by erosion or deposited by the wind; a mass noun without a plural.
maximum maximums
maxima
In general usage, maximum is the highest possible value that can be assigned to something, and minimum is the least possible. On a scale of 1 to 10, for example, 10 is the maximum and 1 the minimum. If the highest and lowest values actually recorded are 8.3 and 2.1, those are not the maximum and minimum. The plurals end in -s.

In geology, a geophysical anomaly with values greater than those in neighboring areas; e.g., a gravity maximum. Also, glacial maximum; pl. maxima.

medium media
mediums
1. An environment (air, soil, water) through which a force acts.

2. A substance (rock, agar) in which specimens are preserved.

3. An agency, means, or instrument (newspapers are a popular advertising medium; the news media are important). Note: Mediums generally refers to psychics.

minimum minimums
minima
A geophysical anomaly with values smaller than those in neighboring areas; e.g., a gravity minimum. Also, glacial minimum. (See maximum.)
stadium stadiums A unit of length.
stadia stadias An instrument for measuring distance.
stratum strata A bed of sedimentary rock.

GeoCollectives

Kudos to Retta Whinnery for her Geogrammar article (Summer 1996 Blueline) entitled: “Minding our keys and ques (or cues).” My only regret is that she did not also include “queue,” a line of waiting people, which is sometimes mispronounced “key” but which is correctly pronounced as in “cue.”

Hansen’s clever list of geocollectives (Summer 1996 Blueline) was well worth repeating. Below is a list of what I hope are some worthy additions.

A gusher of petroleum geologists A retort of geochemists
An avalanche of geomorphologists An outpouring of igneous geologists
A layering of sedimentologists A fabric of metamorphic geologists
A howl of heavily edited geowriters A wave of geophysicists
A nitpick of editors A cluster of astrogeologists
A gleam of gemmologists A surge of oceanographers
A facet of crystallographers  
—Sardonyxly yours, Butch Grossman