haem (countable and uncountable, plural haems)
- Australia, Canada, Ireland, New Zealand, South Africa, and UK standard spelling of heme.
- 2010, Pierre Cornelis and Simon Andrews (editors), Iron Uptake and Homeostasis in Microorganisms, page 17:
- Haem is ubiquitous, abundant and necessary for energy metabolism. Most bacteria have a haem biosynthesis pathway, but nevertheless, since haem is a major source of iron (an essential metal), microbes take up exogenous haem to retrieve iron.