The 1689 Second London Baptist Confession of Faith describes the Church this way:
26.1 The catholic or universal church, which (with respect to the internal work of the Spirit and truth of grace) may be called invisible, consists of the whole number of the elect, that have been, are, or shall be gathered into one, under Christ, the head thereof; and is the spouse, the body, the fulness of him that filleth all in all.
English Particular Baptists, like their Presbyterian brethren, viewed the Church as the called-out people of God, with Christ as its head. They looked at verses like Ephesians 5:25-27 as describing the Church, not individual assemblies:
Ephesians 5:25-27 25 Husbands, love your wives, just as Christ also loved the church and gave Himself up for her, 26 so that He might sanctify her, having cleansed her by the washing of water with the word, 27 that He might present to Himself the church in all her glory, having no spot or wrinkle or any such thing; but that she would be holy and blameless.
(All emphasis describe the church)
English Particular Baptists also recognized the Church as represented in individual assemblies which they termed particular societies, congregations, or churches:
26.2 All persons throughout the world, professing the faith of the gospel, and obedience unto God by Christ according unto it, not destroying their own profession by any errors everting the foundation, or unholiness of conversation, are and may be called visible saints; and of such ought all particular congregations to be constituted.
26.5 In the execution of this power wherewith he is so intrusted, the Lord Jesus calleth out of the world unto himself, through the ministry of his word, by his Spirit, those that are given unto him by his Father, that they may walk before him in all the ways of obedience, which he prescribeth to them in his word. Those thus called, he commandeth to walk together in particular societies, or churches, for their mutual edification, and the due performance of that public worship, which he requireth of them in the world.
Particular Baptists were in agreement with other Reformed denominations that worship and the ordinances (sacraments according to other Reformed denominations) could only be performed in local assemblies.
The Particular Baptist view of the Church is not held by all Baptists. In fact, the issue has been hotly contested and is one of the leading reasons why there have been many schisms and church splits over the past 300+ years.