不可以。“down payment”其实与“定金”的含义差别较大。

Black’s Law Dictionary对于down payment一词的定义是：

The portion of purchase price which is generally required to be paid at time purchase and sale agreement is signed and generally paid in cash or its equivalent.

由此可知，down payment只是签订合同时支付的部分购价，它不具备“定金”所具有的质押（pledge）及担保的含义，也不会使买方能因卖方违约而获得双倍赔偿的权利。

因此，为避免误导，最好将down payment译为“头款”或“首期付款”，尽管目前很多词典都将它当作定金。

而汉语里的“定金”则应当翻译成deposit或earnest money，它们才具有质押性质。

以下为相关双语示例，供参考：

They will receive a subsidy equivalent to half of the net rental they have paid during the tenancy period, and use it for part of the down payment. 

他们会获得等同于在租住期间所缴纳的一半净租金的资助，用作缴付部分头款。 

STH advised that the objective of MHPP was to enable eligible applicants who did not have sufficient savings for down payment to rent a MHPP flat first and then consider buying the [...] flat later using the Purchase Subsidy.

运输及房屋局局长表示，置安心计划的目标是让没有储蓄足够款项支付首期的合资格申请人，先租住置安心计划的单位，再考虑于稍后利用置业资助购买单位。