first

名词 first:

1. the first or highest in an ordering or series
   同义词：number one
2. the first element in a countable series
   同义词：number one, number 1
3. the time at which something is supposed to begin
   同义词：beginning, commencement, outset, get-go, start, kickoff, starting time, showtime, offset
4. the fielding position of the player on a baseball team who is stationed at first of the bases in the infield (counting counterclockwise from home plate)
   同义词：first base
5. an honours degree of the highest class
   同义词：first-class honours degree
6. the lowest forward gear ratio in the gear box of a motor vehicle; used to start a car moving
   同义词：first gear, low gear, low

形容词 first:

1. preceding all others in time or space or degree
2. indicating the beginning unit in a series
   同义词：1st
3. serving to set in motion
   同义词：inaugural, initiative, initiatory, maiden
4. serving to begin
   同义词：beginning
5. ranking above all others
   同义词：foremost, world-class
6. highest in pitch or chief among parts or voices or instruments or orchestra sections
7. being the gear producing the lowest drive speed
   同义词：low

副词 first:

1. before anything else
   同义词：firstly, foremost, first of all, first off
2. the initial time
   同义词：for the first time
3. before another in time, space, or importance
4. prominently forward
   同义词：foremost

1. First of all she just smiled, then she started to laugh.
   最初她只是微笑，後来才放声大笑。
2. First off, let's see how much it'll cost.
   首先，让我们看看要花多少钱。
3. He was the first to be there.
   他是第一个到达那里的。
4. Sunday is the first day of the week.
   星期日是一周的第一天。
5. Read the text first and then explain the new words.
   先读课文，然后解释生词。

first

n.（名词）
The ordinal number matching the number one in a series.
第一：一个系列中的相配数字一的序数
The one coming, occurring, or ranking before or above all others.
首要：在到来、发生或排衔上比其它居先的
The beginning; the outset:
开头；开始：
例句：
from the first; at first.
从头开始；起先

Music The voice or instrument highest in pitch or carrying the principal part.
【音乐】 高音部，主奏乐器：在音调上最高的声音或乐器，或演唱或演奏主要部分
The transmission gear or corresponding gear ratio used to produce the range of lowest drive speeds in a motor vehicle.
头档，低速齿轮：限定机动车辆最低驾驶速度范围的传动齿轮或对应齿轮的比率
The winning position in a contest:
第一名，冠军：竞赛中处于胜利的地位：
例句：
finished the season in first.
以第一名结束了赛季

Baseball
【棒球】
First base.
第一垒
A first baseman.
一垒手
adj.（形容词）
Corresponding in order to the number one.
第一位的：按顺序排在第一位的
Coming before all others in order or location:
首先的，最前的：在顺序或方位上比其它人（事）领先的：
例句：
the first house on your left.
在你左边的第一间房子

Occurring or acting before all others in time; earliest:
最早的：在时间上比其它人（事）先发生或先行动的；最早的：
例句：
the first day of spring.
春季的第一天

Ranking above all others, as in importance or quality; foremost:
第一流的：在重要性或质量上排衔在其它之上的；最前面的：
例句：
was first in the class.
在班上数第一的

Music Being highest in pitch or carrying the principal part:
【音乐】 第一声部的，高音部的：声调最高的或演唱（奏）主要部分的：
例句：
first trumpet.
高音号

Of, relating to, or being the transmission gear or corresponding gear ratio used to produce the range of lowest drive speeds in a motor vehicle.
头档的，低速齿轮的：限定机动车辆最低驾驶速度范围的传动齿轮或对应齿轮比率的或与之有关的
adv.（副词）
Before or above all others in time, order, rank, or importance:
第一地，首要地：在时间、秩序、地位或重要性上比其他人（或物）居前或在上的：
例句：
arrived first; forgot to light the oven first.
第一个到达；忘了先点上炉子

For the first time.
第一次地
Rather; preferably:
宁可；宁愿：
例句：
would die first.
宁愿死

In the first place; to begin with.See Usage Note at firstly
首先；以…开始参见 firstly

来源：
Middle English
中古英语
from Old English fyrst * see per
源自 古英语 fyrst *参见 per