irregular

Everyday

1. Irregular means not even or not the same shape or size all over: "an irregular coastline". tree →
2. Irregular means not happening at equal times: "an irregular heartbeat", "irregular meals". tree →
3. In grammar, irregular verbs and plurals do not follow the normal rule: go → went, child → children. tree →
4. (formal) Irregular can mean not following the usual rules, not proper: "irregular behaviour". tree →

In the lessons

In maths, an irregular shape (an irregular polygon) has sides or angles that are not all equal; its area is often found by splitting it into rectangles or counting squares. In grammar lessons, irregular verbs must be learned by heart. In health, an irregular pulse is checked by a doctor. Phrases: irregular shape, irregular polygon, irregular verb, at irregular times.

Examples

• A rectangle that is not a square is an irregular quadrilateral. tree →
• Find the area of the irregular shape by counting squares. tree →
• "Swim" is an irregular verb: swim, swam, swum. tree →
• The plural of "mouse" is irregular: mice. tree →
• The bus comes at irregular times. tree →
• The country has an irregular coastline with many bays. tree →
• The doctor heard an irregular heartbeat. tree →
• The streets were rather irregular, it is true, but still this added to their picturesque appearance. tree →

Note

Opposite: regular. Spelling: double r (ir- + regular). In maths, a regular polygon has all sides and all angles equal; any other polygon is irregular. Irregular verbs do not take -ed in the past.