Charles Sanders Peirce, the eminent American philosopher who is widely credited with many important contributions to modern thought, lived much of his adult life in dire poverty and was forced to take paid employment where he found it. Among his myriad writing gigs was a considerable stint in lexicography: he contributed about 6,000 definitions to The Century Dictionary and edited many more. I examine Peirce's definitions in the context of his other writing and intellectual pursuits. Using the API supplied by Wordnik and Sketch Engine software, I have also constructed two corpora from Century definitions, representing those written by Peirce and those written by others, in order to look at the statistical properties of his lexicographic output. Examination of the corpora at the macro level reveals no significant differences between the definitions written by Peirce and by others, but individual study of Peirce's definitions in this great American dictionary is a source of insight into his interests, preoccupations, and analytical approach that has so far scarcely been tapped.