Blackleg

Part of speech: noun

Definitions

1. A disease of cattle and sheep caused by a bacterium that produces gas in muscle tissue and sudden death, or a strikebreaker who crosses picket lines during labor disputes
2. A bacterial infection affecting livestock that causes rapid gas accumulation in muscles and death, or a worker who breaks strike lines during labor actions
3. An acute infectious disease in farm animals characterized by muscle gangrene and mortality, or someone who undermines labor union efforts by working during strikes

Etymology: The word "blackleg" is a plain compound of "black" and "leg," and its two senses grew from that simple pairing rather than from any single famous coinage. The livestock disease got its name from the dark, swollen lesions that form on an animal's leg and hindquarters, which is where the infection often shows up first. The strikebreaker sense came later, applied to a worker who crosses a picket line and so goes against the rest of the workforce. The connection between the two senses is more loose than a neat story would suggest. Both uses name something that looks wrong on the leg or in the trade, and English speakers reached for the same compound for each. Nothing in the record ties one meaning to a specific person or event, so the sense of the word is best understood as two separate applications of a descriptive pairing.