That is to say, while most volumes on the shelf were in the expected form of Latin -> Modern English, this battered little book had all its entries in the form Middle English -> Latin. A thoughtful man called Father Geoffrey compiled it in about 1440, presumably for the aid of those people who were now beginning to write some documents in Latin but had not been trained to it. And I spent about two hours being utterly charmed.
There were the simple entries:
CUMPANY comitiva.Then there are the ones that need a little clarification, because they could mean different things:
CRYSTEN manne or womanne [ie, adjectective/noun rather than verb]. Cristianus, Cristiana.And, the croce being the cross-topped staff a bishop carries, I'm suspecting that croce and crocea are the ancestors of our 'crutch'. Then he has to distinguish between different uses of the same word in English for which the Latin translation will vary:
LENTE, holy tyme. Quadragesima.
CROCE of a byschope. Pedum, cambuca, crocea.
CLERE, as wedur ys, bryghte. Clarus, serenus.The root word seems to usually come before its derivatives, even if they ought alphabetically to precede it. So CLEYME comes before CLEYMARE (and, for some reason, CLEYSTAFFE precedes them both). And sometimes the order is just a bit random:
CLERE, as water, or oþer licour. Limpidus, perspicuus.
CLERE of wytt, and undyrstondynge. Perspicax.
EEM, moderys brothere. Avunculus.
EEM, faderys brothere. Patruus.
FEE foedus.And of course, this being Middle English, sometimes a word is not only listed out of order relative to the words immediately surrounding it, but under an entirely different letter to what you'd expect:
FEDYN' wythe mete. Cibo, pasco, esco.
FEEDE chyldryn, wythe pappe mete. Papo.
IVYL, or wykkyd. Malus, iniquus.Verbs are all listed, not by their infinitive, but with a final -YN'. I can't help but wonder if that was the editor mistaking the infinitive for the gerund and putting in an apostrophe to indicate it.
KNAWYN', or gnawyn, or fowly bytyn. Corrodo.But this rule broke down a little when it came to 'have', because of the multitude of little phrases that use that verb to form another meaning (like 'avere fame', 'to have hunger' (be hungry) in modern Italian):
DRYNKE [the noun]. Potus, poculum, pocio.
DRYNKYN'. Bibo, poto.
DRYNKYN' a-yeen. Rebibo, repoto. [Really, how often do you need to use that?]
HAVE ABhomynacyon, and have disdeyne [despise], supra in HAN.There are words that delightfully evoke the texture of daily life:
HAVE in mende [remember]. Recordor, memoro, memini.
HAVE levyr [prefer]. Malo.
LYNT, schauynge of lynen clothe. Carpea, secundum sururgicos.And words you really hope people wouldn't have had cause to use nearly so regularly:
BEKEN with the iye, Annuto, conniveo. Connivet hic oculis, annuit ipse manu.
GELT MAN spado, eunuchus.Then there are the words that you've never come across before but are just wonderful words that you immediately resolve to use in your own everyday life:
DROBLY, DRUBLY. Turbulentus, turbidus.Is this a dictionary? Well, maybe not by modern standards, the same way we might choose not to call anyone living in the 14th century a real historian, no matter how accurate their chronicle. And it's only one way - for the English speaker writing in Latin, no help to anyone translating the letter they received in answer. The irregularity of spelling and alphabetisation mean that it's a bit tricky for use as a reference tool, and you have to be willing to search under different spellings or synonyms to find the word you want. But that would not be such an inconvenience to people who are accustomed to taking a long time over books and letters as it would be to a 21st century writer who expects information to spring to one's fingertips.
I don't think it is a dictionary quite yet, depending on your interpretation of the term, of course. I'd call it a word list, a translation tool, because I'd expect a dictionary to be more comprehensive both in the number of words it includes and its explanations of those words. Still, in compiling it, you can see Frater Galfridus considering and dealing with questions of scope, intent and ordering, questions that may be answered differently by the next person to undertake a similar task, but all the more easily for having been posed before.
It's a start!
 Frater Galfridus. Promptorium parvulorum sive clericorum. Ed. Way, Albert. Camden Society OS 25, 54, 89. 3 vols. London, 1843-1865. Camden Society listing here. There is also an EETS version published in 1908, but I couldn't find that.