Femicide, also called gynocide, is a killing in general, while the others focus on family members. Another difference is femicide is the killing of women, while the others are all male.

Femicide: the systematic killing of women

Patricide: the killing of one's father

Fratricide: the killing of one's brother

Nepoticide: the killing of one's nephew.

There are more names for male killings (patricide - father, fratricide - brother, nepoticide - nephew, avunculicide - uncle, mariticide - husband) then there are names for female killings (matricide- mother, sororicide - sister, uxoricide - wife). Almost all other homocides, family or in general, are not gender-specific.

More Info: en.m.wikipedia.org