day 1 vs day one

Both 'day 1' and 'day one' are correct, but they are used in different contexts. 'Day 1' is commonly used to refer to the first day of an event, project, or journey, while 'day one' is often used to indicate the beginning or starting point of something. The choice between the two depends on the specific context in which they are being used.

Last updated: March 30, 2024 • 927 views

day 1

This phrase is correct and commonly used to refer to the first day of an event, project, or journey.

Use 'day 1' when referring to the specific first day of an event, project, or journey. It is a concise way to indicate the initial day.

Examples:

We will start the training program on day 1 of the conference.
On day 1 of the trip, we visited the famous landmarks in the city.

Show examples from the web [+]

Patient monitoring on day 1 should include vital signs, including pulse, blood pressure and respiratory rate.
There was no evidence of protection from disease caused by vaccine HPV types for which subjects were PCR positive at day 1.
And Ryan dumped me... day 1.
He's been gunning for Freddie since day 1.
Rituximab is the medication which is given to you on day 1 or directly before Zevalin treatment (see 3.
3 mg on day 1, 10 mg on day 2 and 30 mg on day 3, as long as each dose is well tolerated.
on day 1, possibly repeated once within 3 days
on day 1, possibly repeated once within 3 days
3 mg on day 1, 10 mg on day 2 and 30 mg on day 3 assuming that each dose is well tolerated.
On your first visit (day 1) you will be given o One rituximab infusion
After administration, fluoxetine readily appeared in plasma with mean Tmax values ranging from 1.25 to 1.75 hours on day 1 and from 2.5 to 2.75 hours on day 21.
Plasma levels readily declined with mean t1/2 values ranging from 4.6 to 5.7 hours on day 1 and from 5.1 to 10.1 on day 21.
A total of 156 patients were randomised to treatment with 5-FU (800 mg/ m2 per day, continuous infusion on days 1 to 5 every 3 weeks) and cisplatin (80 mg/ m2 as a 2-hour infusion on day 1, every 3 weeks).
The apparent clearance of ara-G (Cl/ F) is comparable between the two groups [9.5 l/ h/ m2 (35%) in adult patients and 10.8 l/ h/ m2 (36%) in paediatric patients] on day 1.
hour infusion on day 1 every 3 weeks) and 5-FU (200 mg/ m2 daily given by continuous infusion via a central line).
hour infusion on day 1 every 3 weeks), and Xeloda (625 mg/ m2 twice daily continuously).
a 2 hour infusion on day 1 every three weeks), and 5-FU (200 mg/ m2 daily given by continuous infusion via a central line).
a 2 hour infusion on day 1 every three weeks), and Xeloda (625 mg/ m2 twice daily continuously).
Ondansetron was administered intravenously 30 minutes prior to chemotherapy treatment on Day 1.
Dexamethasone was administered 30 minutes prior to chemotherapy treatment on Day 1.

Alternatives:

the first day
the initial day
day one

day one

This phrase is correct and often used to indicate the beginning or starting point of something.

Use 'day one' to emphasize the starting point or beginning of a process, journey, or experience. It conveys the idea of the initial stage.