What is meant by offering the ‘aqiqah on the seventh day

If what you mean is the ‘aqiqah that is slaughtered on behalf of the newborn, it is slaughtered on the seventh day, because of the hadith of Samurah ibn Jundub (may Allah have mercy on him), who said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Every child is in pledge for his ‘aqiqah, which may be sacrificed for him on the seventh day, and he should be given a name and his head should be shaved.” Narrated by at-Tirmidhi (1522), an-Nasa’i (4220) and Abu Dawud (2838). The hadith was classed as sahih by al-Albani in al-Irwa’ (4/385).

Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) said: The words “which may be sacrificed for him on the seventh day” mean that it should be slaughtered on the seventh day. In other words, it is Sunnah to slaughter it on the seventh day. So if the child was born on Saturday, it should be slaughtered on Friday, one day before the day of the week on which he was born. This is the basic principle. And if he was born on Thursday, then it should be slaughtered on Wednesday, and so on."(Ash-Sharh al-Mumti‘  7/493).

Based on that, you should slaughter the ‘aqiqah on Wednesday in the morning, or during the day.

With regard to naming the child, he may be given his name on the first day, or the seventh, because of the hadith of Anas ibn Malik (may Allah be pleased with him), who said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Last night a boy was born to me, and I have named him after my father, Ibrahim.” Narrated by Muslim (3126).

It was narrated that ‘A’ishah (may Allah be pleased with her) said: The Messenger of Allah (blessings and peace of Allah be upon him) offered ‘aqiqah on behalf of al-Hasan and al-Husayn on the seventh day, and gave them their names. Narrated by Ibn Hibban (12/127) and al-Hakim (4/264). Classed as sahih by al-Hafiz Ibn Hajar in Fath al-Bari (9/589).

There is nothing wrong with slaughtering the ‘aqiqah on any day; the same applies to naming the child.

And Allah knows best.