The word "Tazkiah" has been mentioned several times and in different forms in the Holy Qur’an. It means the attestation of someone's honorable record, or to purify one's self. For instance, the following verses spoke of "Tazkiah":
"Truly he succeeds that purifies it," (91: 9)
"Hast thou slain an innocent person," (18: 74)
"(To announce) to thee the gift of a holy son." (19: 7)
"That is (the course making for) most virtue and purity amongst you." (2: 232)
The meaning of the first verse is to purify one's self from evil characteristics which develop from corrupt nutrition, excessive speech, anger, envy, greed, self and material worship, conceit and vanity. This type of purification is performed by abandoning such traits and adhering to the noble characteristics which contradict the above mentioned ones.
The second verse means: Have you killed someone who, I attest to his honourable record, for he has not committed a crime, or, an action, which necessitates punishing?
The third verse speaks of granting a prophet a virtuous son made pure from all sins, and whose nations conform to goodness. Lady Fatima az-Zahra (sa) is “Zakiyah” in all the above-mentioned meanings. This is understood from the verse of purification, which we have already discussed, and concluded that she was pure of all abominations, or, "Rijs."
As for the fourth verse, you can refer to the study in regard to her name "Al-Mubarakah", for here we have explained the purification meant in this verse.