A Grammatical Dictionary of Botanical Latin

Span (measure of length), “the distance from the end of the thumb to the end of the little finger of a spread hand; an English unit of length based on this distance equal to 9 inches; the distance between the tips of the middle fingers when the arms are stretched to the side as far as possible from the body” (WIII); see spithama,-ae (s.f.I); see palmus,-i (s.m.II); see dodrans,-antis (adj.- part.B).

NOTE: there is a discrepancy in classical glossaries and some botanical ones between the Roman ‘span’ and the Greek one. The Roman span of Lewis and Short is nine inches (the same as the English span). However, the Greek span is only seven inches - a discrepancy of two inches. The discrepancy seems to derive from the choice of distance between the thumb and:

1. the little finger (nine inches: Roman and English): the palmus,-i (s.m.II); the dodrans,-antis (s.m.III); the English ‘span.’ [approx. 24 cm.)

2. the forefinger (seven inches: Greek): the spithama,-ae (s.f.I).

[approx. 19 cm.)

The confusion of the Greek span with the Roman seems to be followed by Liddell and Scott who equate the Greek spithama with the Roman dodrans (see spithama,-ae (s.f.I).

NOTE: A digitus,-i (s.m.II) is 3/4 of an inch; twelve of them would equal 9 inches, or a Roman span: the palmus,-i (s.m.II) and dodrans,-antis (adj.part.B).

span-long (adj.): dodrantalis,-e (adj.B), dodrantarius,-a,-um (adj.A): of nine inches (the English ‘span’), nine inches long; of or belonging to a dodrans; cf. spithameus,-a,-um (adj.A): 7 inches, a [Greek] span long or high.