Superfecundation is the fertilization of two or more ova from the same cycle by sperm from separate acts of sexual intercourse. The term superfecundation is derived from fecund, meaning the ability to produce offspring. Heteropaternal superfecundation occurs when two different males father fraternal twins. In common usage, the term superfecundatio...
• (n.) Fertilization of two ova, at the same menstruation, by two different acts of coition.
Offspring sired by different males in the same litter. 
(soo″pәr-fe″kәn-da´shәn) fertilization of two or more oocytes during the same ovulatory cycle, by separate coital acts.
Su`per·fec`un·da'tion noun (Physiol.) Fertilization of two ova, at the same menstruation, by two different acts of coition. 
An uncommon occurrence in hich two eggs are fertilized within a short amount of time, but not at the same sexual act and not necessarily by the same man.
[n] - fertilization of two or more ova released during the same menstrual cycle by sperm from separate acts of coitus (especially by different males)
superfecundation 1. Successive fertilization by two or more separate instances of sexual intercourse of two or more ova formed during the same menstrual cycle. Fertilization may be by the same male or by two different males. 2. The fertilization of two or more ova by spermatozoa from different acts of coitus, thus allowing the production of litter-...
noun fertilization of two or more ova released during the same menstrual cycle by sperm from separate acts of coitus (especially by different males)
the fertilization of two or more ova discharged at the same ovulation by successive acts of sexual intercourse.