名詞 initial:

1. the first letter of a word (especially a person's name)

動詞 initial:

1. mark with one's initials

形容詞 initial:

1. occurring at the beginning

1. The initial `h' in `hour' is not aspirated.
   hour一字中起首的h不發(fā)送氣音。
2. The word `hour' is pronounced without an initial aspirate.
   hour一字的開頭字母h不發(fā)送氣音。
3. The government underwrotethe initial costs of the operation.
   政府為該項活動提供了開辦時所需的費用。
4. The new aircraft has performed very well in its initial trials.
   這種新式飛機在最初幾次試飛中表現(xiàn)性能良好。
5. After she'd overcome her initial shyness, she became very friendly.
   她克服了開始時的羞澀之后，就變得非常友善。
6. Please write down your initials on each page of the paper.
   請在每頁考卷上寫下名字的首字母。

in.i.tial

adj.（形容詞）
Of, relating to, or occurring at the beginning; first:
開始的：開始的，與開始有關(guān)的，發(fā)生在開始的；首先的：
例句：
took the initial step toward reconciliation.
采取了走向和解的第一步

Designating the first letter or letters of a word.
首字母的：一個單詞的第一個或前幾個字母
n.（名詞）

The first letter of a proper name.
專有名詞的第一個字母
initials The first letter of each word of a person`s complete name considered as a unit:
initials 人名每一部份的第一個字母：
例句：
stationery monogrammed with her initials.
印有她姓名首字母的信箋

The first letter of a word.
字首：單詞的第一個字母
A large, often highly decorated letter set at the beginning of a chapter, verse, or paragraph.
（書刊、文章中段落、章節(jié)等）特大的大寫首字母：一章、一首詩或一個段落的第一個字母，大而且通常極具裝飾性
v.tr.（及物動詞）
in.i.tialed 也作 in.i.tialled in.i.tial.ing in.i.tial.ling in.i.tials in.i.tials
To mark or sign with initials, especially for purposes of authorization or approval.
用姓名的首字母簽名：標(biāo)出或用首字母簽名，尤指用于表示授權(quán)或同意

來源：
Latin initi3lis
拉丁語 initi3lis
from initium [beginning] * see ei-
源自 initium [開始] *參見 ei-

【引伸】
ini.tially
adv.（副詞）
ini.tialness
n.（名詞）