The series of bodily changes that occur in the female of most mammals from one period of estrus to another. The estrous cycle usually takes place during a specific period known as the breeding season, which ensures that the young are born at a time when the chance of survival is greatest.
ear-to-ear. It's about smiling. Ear-to-ear smile or grin is when you have a very broad and generous smile. Such a smile when each corner of your mouth is by each of your ears. Explain to me why you don't have an ear-to-ear grin right now.
XD is the acronym for the phrase LOL or Laugh Out Loud. It is an emoticon with the letter X as eyes and D as a laughing mouth. The eyes here appear as squinted that denotes the expression of a person while laughing really hard. Usage When a person sends XD then it is an emoticon that denotes laughter. It is used after someone has sent a joke or said something funny. There can be questions regarding what does xd mean but in essence it is simple.