Pronunciation: [jˈɛstə dˈe͡ɪz] (IPA) 
The spelling of "yester days" might be confusing for some English learners. However, it is pronounced as /ˈjɛstər deɪz/. The first syllable is pronounced as "yest" with a short vowel sound, followed by "er" with a schwa sound, and "days" with a long "a" and a slight glottal stop at the end. The correct spelling of this phrase is "yesterdays" without a space. It refers to the past, particularly the previous day or days.
Yester days is a noun phrase with two components: "yester" and "days." Taken together, it refers to the past, particularly the days that are no longer present, referring to the previous day or former times.
The term "yester" is a contraction of "yestern," which is an archaic form of "yesterday." It indicates the time period directly preceding the current day or the recent past. It suggests a sense of nostalgia and reminiscence.
"Days" refers to a series of 24-hour periods that make up time, commonly associated with the cycle of light and darkness caused by the Earth's rotation. It is a measure of time that is used to track and describe various events, experiences, or moments.
When combined, "yester days" represents the collective sum of previous days, reflecting on the time that has passed and the experiences endured during those periods. It encompasses events, memories, and occurrences that have taken place before today, presenting a nostalgic view of bygone times.
The term "yester days" is often utilized in literature, poetry, and expressions to evoke a sentimental longing for the past or to emphasize the contrast between the present and a time that is no longer. It serves as a reminder of the constant movement of time and invites reflection on the changes that have occurred.
The word yesterdays is a compound noun derived from two elements: yester- and -days.
The first part, yester-, is an archaic form of the word yesterday. It is derived from the Middle English word yisterday, which was formed by combining yister (meaning yesterday) and the suffix -day (indicating a time period). Yister ultimately traces back to the Old English word geostran dæg, where geostran means yesterday.
The second part, -days, is a plural form of the noun day, indicating a specific period of time.
Thus, yesterdays literally means the days before today.
