Pronunciation: [dˈe͡ɪz ˈə͡ʊld] (IPA) 
The spelling of the phrase "days old" is fairly straightforward. "Days" is spelled d-ey-z, with a long "a" sound and a "z" at the end. "Old" is spelled o-l-d, with a short "o" and a "d" at the end. Together, they make up the phrase "days old" pronounced as dey-z ohld. This phrase is commonly used to describe the age of an infant or animal in days, and is often seen on social media posts or announcements.
Days old is an adjectival phrase used to denote the age or duration of something, specifically referring to the number of days that have passed since a particular event or starting point. This term is commonly used when describing the age of living beings, objects, or even concepts.
Days old is typically employed to quantify the elapsed time since birth, inception, creation, or another significant milestone. It emphasizes the number of full days that have transpired, excluding the present day. For instance, if a baby is one day old, it means a single day has passed since its birth, but it has not yet completed two full days of existence. Therefore, "one day old" signifies that the baby has spent a full 24 hours in the world.
The phrase "days old" can also be applied to non-living things like food or perishable items, indicating how long they have been in existence since production, packaging, or harvesting. Additionally, it is applicable to abstract notions such as ideas, plans, or projects, measuring the time since their initiation or conception.
In conclusion, days old is a descriptive phrase quantifying the number of days that have transpired since a specific event or starting point, commonly used to express the age or duration of living beings, objects, or concepts by excluding the present day.
The term "days old" does not have a specific etymology on its own, as it is a common expression in English used to describe the age of an individual or object in terms of the number of days that have passed since its birth or creation. However, each component of the phrase has its own etymology.
1. Days: The word "day" comes from the Old English word "dæg", which can be traced back to the Proto-Germanic word "dagaz". This term is thought to be related to the Indo-European root "*dʰegʷʰ-" meaning "to burn" or "daylight".
2. Old: The word "old" originated from the Middle English words "old" or "olde", which are derived from the Old English word "eald".
