لِكَيْ (likay) is an Arabic conjunction that means "in order that" or "so that." It’s used to introduce a subordinate clause that expresses the purpose of the main clause.

Here’s how it works:

Followed by the subjunctive: An important thing to remember is that the verb in the clause following لِكَيْ will be in the subjunctive mood (منصوب). This is because the action is not yet definite, but rather something hoped for or intended.

Examples:
ذهبتُ إلى السوق لِكَيْ أشتريَ بعضَ الفاكهةِ. (dhahabtu ila as-suq likay ashtariya ba’d al-fakhah.) – I went to the market in order to buy some fruit.
يدرسُ بجدٍّ لِكَيْ ينجحَ في الامتحانِ. (yadrusu bi-jiddin likay yanjaha fi al-imtihan.) – He is studying hard so that he may succeed in the exam."