International Standard Bible Encyclopedia 
lid´i - a ( Λυδί , Ludı́a ): The feminine of Lydian, a native of Lydia, a large country on the West of Asia Minor, and the name of Paul's first convert in Europe. This name was a popular one for women (compare Horace Odes i. 8; iii. 9; vi. 20), but Ramsay thinks she "was familiarly known in the town by the ethnic that showed her origin" ( Hdb , under the word "Lydia"; compare St. Paul the Traveler , 214). It has always been and is still a common custom in the Orient to refer to one living in a foreign land by employing the adjective which designates the nationality. Renan thinks it means "the Lydian"; Thyatira is a city of Lydia. Lydia was (1) living in Philippi, (2) of the city of Thyatira, (3) a seller of the purple-dyed garments from her native town, (4) and "one that worshipped God." Her occupation shows her to have been a woman of some capital. The phrase which describes her religion ( seboménē tón Theón ) is the usual designation for a proselyte. She was in the habit of frequenting a place of prayer by a riverside, a situation convenient for the necessary ablutions required by the Jewish worship, and there Paul and his companions met her. After she had been listening to Paul (Greek imperfect), the Lord opened her heart to give heed to his teaching ("To open is the part of God, to pay attention that of the woman," Chrysostom). Her baptism and that of her household followed. To prove her sincerity she besought the missionaries to accept the hospitality of her home. Her house probably became the center for the church in Philippi ( Acts 16:14 , Acts 16:15 , Acts 16:40 ). Lydia is not mentioned in Paul's letter to the Philippians, but, if Ramsay be correct, she may have been Euodias or Syntyche ( Philippians 4:2 ).