Irregular period is the same as a period. Irregular just means no set pattern, for example your period might come 1 week after you finished your first one or it might come after 3months or so.
meter
It is irregular.
It is an irregular polygon.
Not necessarily. A rhombus is an equilateral quadrilateral but does not have a line of symmetry. An irregular octagon does not, either.
It is irregular
It is general, because the pattern is irregular.
Fracture is when minerals are broke with an irregular. The pattern is not right.
An irregular verb, for instance: TO BE, CAN, etc.
irregular with a pattern
Yes, some are big some are small.
In English, there are only two verbs that are irregular in the present tense: to be (am/are/is/are/are/are) to have (have/have/*has*/have/have/have) The modal verbs follow a different pattern than regular verbs but are not technically "irregular": will shall must etc.
The reason why a verb would be called irregular is that it does not conform to any general rule about how it forms different tenses or conjugations; each irregular verb has its own individual pattern. You just have to learn them one at a time.
Irregular period is the same as a period. Irregular just means no set pattern, for example your period might come 1 week after you finished your first one or it might come after 3months or so.
meter
What makes some verbs irregular is the way the tenses change for those verbs. A regular verb changes according to a pattern: play, plays, played, etc. For an irregular verb, it changes to something seemingly random: awake, awoke, etc.
In the sentence you want to sleep when you are tired the words to sleep are an irregular verb. Verbs who do not follow the typical pattern for conjugation are called irregular verbs.