One who desires lactating breasts, often as a sexual fetishism. A true, genuine lactophiliac would consider their desire to nurse one of their basic human needs. Such strong desires are often the leading force in the ANR community- one focused around Adult Nursing Relationships or Adult Breast Feeding. Their are also women who have a strong desire to feed or lactate for another person. Some of these relationships are more focused on nurture and abstain from other sexual aspects in the relationship completely.
A Lactophiliac is someone who's sexually aroused by lactating breasts, usually they will focus on a woman's breasts more than your average normal person.