Fir and fur are easily confused words. The spell-check of most word processing software programs would not catch a slip-up among these three words. As long as it’s a word and it is spelled correctly, spell-check keeps on scanning the document.
Fir is a noun. It means a type of tree that has spiny needles for leaves and that reproduces via cones. Firs, spruces and pines are classified as conifers. Along with their unique leaves and cones, conifers are known for thriving in cold, mountainous climates, remaining green throughout the winter, and having a triangular body shape.
Fur is a noun. It means the soft hair covering of most mammals, and many marsupials. It also means fuzzy fabrics designed to imitate actual fur.
The following sentence uses both words correctly:
Felicity’s favorite things at Christmas were picking out a fir tree for decorating, and wearing her luxurious white fur coat and hat everywhere she went.