Definition

Noun: 1. A type of thistle: A European thistle (Cirsium vulgare) characterized by its large flower heads, very spiny leaves and stems, and a prickly, spherical base (involucre) beneath the flower. It is a common biennial plant that has become widely established as a weed in many regions, including the United States.

Usage Notes

• "Boar thistle" is a common name for a specific, widespread species of thistle. It is often used in botanical, agricultural, or gardening contexts to identify this invasive weed.
• The term is typically used as a countable noun (e.g., "a boar thistle," "several boar thistles").

Examples

• The pasture was overrun with boar thistles, making it difficult for the animals to graze.
• You can identify the boar thistle by its large purple flower head and extremely prickly leaves.
• Boar thistle is considered a noxious weed in many parts of the country.

Advanced Usage

• The plant's scientific name, , is used in formal botanical writing to avoid ambiguity with other thistle species also called "bull thistle" or "spear thistle."

Variants and Related Words

• Bull thistle: The most common synonym for "boar thistle."
• Spear thistle: Another frequent common name for the same species ().
• Plumeless thistle: A name sometimes used, referring to the absence of the feathery pappus (the plume-like structure on the seeds) found on some other thistles.
• Thistle: The general term for plants in several genera (like , , ) known for their prickly leaves and stems.

Synonyms

• Bull thistle
• Spear thistle
• (scientific name)

Related Phrases/Idioms

• Grasp the thistle: An idiom meaning to tackle a difficult problem boldly and directly. While this idiom uses the general word "thistle," the boar/bull thistle, with its formidable spines, exemplifies the kind of challenge the phrase describes.
  • Example: The new manager decided to grasp the thistle and address the department's inefficiencies head-on.

Noun

1. European thistle with rather large heads and prickly leaves; extensively naturalized as a weed in the United States