Please explain the di/di mo/mo twins???

gill • I'm a mother of 5 beautiful babies, 4 girls chloe 10 lucy 4 Molly 3 and Macie 19 months, and my gorgeous son Adam 7 😄 I've been with my husband Cyril for near 9 years and married for 2 and a half xx
I've heard it several times but can't remember lol it confuses me so can someone tell me the difference in them all?