The first link goes to the article in JSTOR (you might not be able to access this) explains the history of the 'chekker' which is the anglicised version of 'eschaquier', which is itself spelt in various ways. The second link is to a brief definition in a glossary.

It seems that nobody is very sure what it was - the first reference to it was in a document of 1360 describing the gift of one, and it seems it was a keyboard instrument that was played with two hands.

To complicate matters, in French the term was later used for subsequent generations of keyboard instruments (what we might call clavichords). So I dare say the precise translation depends on when the instrument in question was made.

Is there any more context, or is this just a list in a vacuum?