purchase

buy, purchase

这两个动词均含“购买”之意。
buy: 普通日常用词，既可指日常随意购物也可指大的购买。
purchase: 正式用词，指大宗购货或购买重要东西。无感情色彩，强调物品的购得。

名词 purchase:

1. the acquisition of something for payment
2. something acquired by purchase
3. a means of exerting influence or gaining advantage
4. the mechanical advantage gained by being in a position to use a lever
   同义词：leverage

动词 purchase:

1. obtain by purchase; acquire by means of a financial transaction
   同义词：buy

1. You can rely on your solicitor's professionalism in dealing with the house purchase.
   你尽可依靠律师处理购房事宜。
2. The purchase price is less if you pay by cash.
   付现金的话，价钱便宜些。
3. They purchased life at the expenses of honor.
   他们以牺牲名誉为代价换得了生命。
4. She made several purchases in the dress shop.
   她在服装店里买了几样东西。
5. He managed to secure a loan to purchase a house.
   他设法弄到一笔贷款买了一栋房子。

pur.chase

v.tr.（及物动词）
pur.chased,pur.chas.ing,pur.chas.es
To obtain in exchange for money or its equivalent; buy.
购买：通过交换货币或其等价物而得到；买
To acquire by effort; earn.
通过努力而获得；挣得
To move or hold with a mechanical device, such as a lever or wrench.
用杠杆移动：用如杠杆或板钳等机械装置移开或控制
n.（名词）

The act or an instance of buying.
购买：购买的动作或例子
Something bought.
被购买的东西
Acquisition through the payment of money or its equivalent.
交换：通过交付货币或其等价物而获得
A grip applied manually or mechanically to move something or prevent it from slipping.
紧抓：用手工或机械装置移动某物或防止其打滑时所使用的牢靠的立足点
A device, such as a tackle or lever, used to obtain mechanical advantage.
似杠杆的设计：如杠杆或滑车等用于取得机械上的方便的设计
A position, as of a lever or one`s feet, affording means to move or secure a weight.
支撑的位置：如杠杆上的位置或某人的双脚等用于移动或支撑重量的位置

A means of increasing power or influence.
手段：扩大力量或影响的方法
An advantage that is used in exerting one`s power.
优势：某人实现权利所使用的利益手段

来源：
Middle English purchasen [to pursue, purchase]
中古英语 purchasen [追求购买]
from Old French purchacier
源自 古法语 purchacier
pur- [forth] from Latin prô- * see per
pur- [向前方] 源自 拉丁语 prô- *参见 per
chacier [to chase] * see chase
chacier [追求] *参见 chase

【引伸】
pur.chaser
n.（名词）